Programming and Web Development Tutorials

Installing the LAMP Server on Ubuntu in Linux Tutorials

Nykc — Sun, 15 Nov 2009 19:56:36 -0600

In this tutorial we are going to install the LAMP server on Ubuntu. I will be installing this on a fairly recent install of Ubuntu 8.04 LTS

The first thing we want to do is install apache2.

Open your terminal and type:

CODE

sudo apt-get install apache2

You will probably be prompted for a password to install as root, enter it and then press "y" to proceed with the install. After everything installs, the following commands will give you the ability to start and stop apache2.

CODE

sudo /etc/init.d/apache2 start

CODE

sudo /etc/init.d/apache2 stop

Once installed point your browser to http://localhost - there you should see a message claiming it worked.

[attachmentid=14895]

The directory you will be working out of is /var/www/

[attachmentid=14897]

That's it time to install PHP.

Open your terminal and type:

CODE

sudo apt-get install php5 libapache2-mod-php5

Once the process completes, restart apache by typing into the terminal:

CODE

sudo /etc/init.d/apache2 restart

To test our install of php open up gedit or your favorite text editor and create a file called test.php

CODE

<?php
phpinfo();
?>

make sure you save it in the /var/www/ directory, open your browser and type http://localhost/test.php to ensure the phpinfo file we created appears and our install was successful.

[attachmentid=14896]

*** When doing this step, my permissions weren't enabled to write/delete files because I wasn't logged in as root. So lets do a change ownership of the directory. There are lots of ways to do this step, but for now just type into your terminal.

CODE

sudo chown nykc /var/www/

be sure to change the [username] with your username...

Ok we are now 2/3 of the way there, all that is left is MySQL.

To install MySQL:

Open up the terminal and type:

CODE

sudo apt-get install mysql-server

you will be advised to create a root password for MySQL - go ahead and create that and continue with the install.

MySQL should now be installed.

Open up the terminal and type the following:

CODE

sudo apt-get install libapache2-mod-auth-mysql php5-mysql phpmyadmin

this will install a program called phpMyAdmin which is a nice graphical tool used to edit your database. Make sure you select apache2 when prompted then continue with the install.

[attachmentid=14898]

Now to get php working with myqsl type the following into the terminal.

CODE

gksudo gedit /etc/php5/apache2/php.ini

find the following commented line in the document.

CODE

; extension=mysql.so

remove the ";" so the line now reads

CODE

extension=mysql.so

now let's restart apache2 again...

CODE

sudo /etc/init.d/apache2 restart

open up your terminal type:

CODE

mysql -uname -p

replace -uname with your -u username enter your newly created password and you are ready to configure.

[attachmentid=14899]

Using Recaptcha to your registration form in PHP Tutorials

felixtgomezjr — Sat, 14 Nov 2009 04:46:01 -0600

Have you seen website registration page lately? See that image where there are texts, words, alphanumeric or phrase that you need to type? That is what we called CAPTCHA (Completely Automated Public Turing test to tell Computers and Humans Apart). Before, if you want to incorporate captcha into your page, you have to make some functions in php to convert your string into an image. And you have to enable image functions of PHP to generate the image. Not this time! No more hassle. Just use reCAPTCHA.

reCAPTCHA is a free, secure and accessible CAPTCHA implementation. Today let us talk on how to incorporate reCAPTCHA to your registration page. I assume that you already know how to make a registration form and that the current task that you are going to do right now is just to integrate reCAPTCHA.

To start with, you have to create a reCAPTCHA account. Follow this link. Once you have created your account, type the domain name. You can choose the �Enable this key on all domains (global key)� if you will be using the key for several domain/websites.

Click the CREATE KEY button. You have to remember your public and private key because you will be using that one in your code. Before we will go back to your code, download this recaptcha library.

Now back to your code. Supposing you have

CODE

<form name=�form1″ method=�post� action=�testformsave.php�>
First name: <input type=�text� name=�firstname� id=�firstname�>
Last name: <input type=�text� name=�lastname� id=�lastname� />
<input type=�submit� name=�cmbsubmit� id=�cmbsubmit� value=�Submit�>
</form>

Insert this code after the Last Name line

CODE

<?php
require_once(�recaptchalib.php�);
$publickey = ��;
echo recaptcha_get_html($publickey);
?>

See to it that the library is on the same path as your registration page. The $publickey should contain the key that you have from reCAPTCHA.

Once that is done, go to your page that handles the form submitted. Let us say you have all ready the script that will save registrant�s data to your database. You can see my other tutorial here. All you have to do is to inject on the top the

CODE

<?php
require_once(�recaptchalib.php�);
$privatekey = � �;
$resp = recaptcha_check_answer ($privatekey,$_SERVER["REMOTE_ADDR"],$_POST["recaptcha_challenge_field"],
$_POST["recaptcha_response_field"]);

if (!$resp->is_valid)
{
die (�The reCAPTCHA wasn�t entered correctly. Go back and try it again.� . �(reCAPTCHA said: � . $resp->error . �)�);
}
else
{
put your code here.
}
?>

The $privatekey variable should contain the key given to you by reCAPTCHA. Thats it! You have made your registration page as spam-free as possible.

Happy coding

File IO with Numberic Data in C++ Tutorials

ImaSexy — Mon, 09 Nov 2009 16:11:19 -0600

This tutorial will demonstrate how to read a file line by line, then show how to manipulate the lines: convert to number, store in vectors, and even tokenize

How do i open a file?

CODE

#include <iostream>
#include <fstream> // needed for file functions

using namespace std;
int main()
{
    ifstream in("yourFile.txt"); // open file for reading

    if(!in.is_open()) // if file is not open - exit
        exit(1);

    in.close(); // close file

    //pause window
    cin.ignore();
    cin.get();

    return 0;
}

simple right?

But how do I read the file?

CODE

#include <iostream>
#include <fstream>
#include <string> // used for getline and string
using namespace std;
int main()
{
    ifstream in("yourFile.txt");

    if(!in.is_open())
        exit(1);

    string line = ""; // The file will buffer every line into this string
    while(getline(in,line)) // loop through the file
    {
        cout<<line<<endl; // output every line to the screen
    }

    in.close();

    //pause window
    cin.ignore();
    cin.get();

    return 0;
}

Getline will loop through every line in the file and it will store that line temporarly in the string

So now you can read a file right? But what if you want to do data operations that involve actual numbers?

CODE

#include <iostream>
#include <fstream>
#include <string>
#include <vector>
using namespace std;

int main()
{
    ifstream in("yourFile.txt");

    if(!in.is_open())
        exit(1);

    string line = "";
    vector<double>numbers(0); // This vector will be used to store all of the data
    while(getline(in,line))
    {
        numbers.push_back(atoi(line.c_str())); //atoi expects a const char so you must convert
    }
    // you now have all of the lines stored in the vector as doubles
    // lets output the vector
    for(int i=0; i<numbers.size(); i++)
        cout<<numbers[i]<<endl; // output to screen

    in.close();

    //pause window
    cin.ignore();
    cin.get();

    return 0;
}

This method works fine if your file is in the following format

QUOTE

12345
12345
12345
12345

But sometimes our data is stored like this in our file

QUOTE

12345 12345 12345 12345
12345 12345 12345 12345

well how do we store the individual numbers? ... by tokenizing

example:

CODE

#include <iostream>
#include <fstream>
#include <string>
#include <vector>
#include <sstream>// used for istringstream
using namespace std;
// this function takes a string pointer and pushes numbers into a
// vector by tokenizing the string at spaces ' '
void parse(string *ext, vector<int>&types)
{
    istringstream iss(*ext);
    string token;
    // you can replace ' ' with whatever you
    // would like to parse at
    while(getline(iss,token,' '))
        types.push_back(atoi(token.c_str())); // push numbers into vector
}
int main()
{
    ifstream in("yourFile.txt");

    if(!in.is_open())
        exit(1);

    string line = "";
    vector<int>numbers(0);
    while(getline(in,line))
    {
        // call our function
        parse(&line,numbers);
    }

    for(int i=0; i<numbers.size(); i++)
        cout<<numbers[i]<<endl; // output to screen

    in.close();

    //pause window
    cin.ignore();
    cin.get();

    return 0;
}

I hope this left you with a farther understand of file IO and using IO for numberic data

Networking tutorial in C++ Tutorials

born2c0de — Sat, 14 Nov 2009 00:40:00 -0600

Well Done. /icon_up.gif" style="vertical-align:middle" emoid=":^:" border="0" alt="icon_up.gif" />

Bash Scripting Basics in Linux Tutorials

Anarion — Fri, 06 Nov 2009 12:34:38 -0600

Hi, In this tutorial we are going to learn how to write bash scripts to do some useful stuff you may need in daily use.

Creating The Script File
fire up your favorite text editor (vim for me) and create a file with no extension, for example, I use "mybackup". So I must write this in the Terminal:

CODE

vim mybackup

Ok, now we created the file itself, what next? here we go...

Writing A Simple Script
In every bash script you write, you must define where your bash interpreter is located. But how can one find where it is? just do this in Terminal:

CODE

which bash

for me, output is: /bin/bash

Now, at first line of your script file (for me it is "mybackup") write the following:

CODE

#!/bin/bash

Simply, it's a "#!" and right after it, the location of your bash interpreter you got with issuing the command "which bash". This was all need to be done in the first line. After it, we are going to actually put our own commands to be executed. The script I want to write is going to be used backup my home directory which contains my personal files and (Top Secret!) projects I do daily.

Ok, in the line after the "#!/bin/bash" in the script, we have to add the command which does the backup process, which is going to be a simple "tar" command to store user's home directory in a single tar file.

CODE

#!/bin/bash
tar -cvf backup.tar /home/kian/

What this command says is: create the tar file "backup.tar" and store the contents of folder "/home/kian" which is my home directory. The "-v" option tells the tar command to print detailed info while executing.

Ok, now I want to show you how to print sentences from your script, you just have to use the command "echo" and give it a sentence to print on screen.

CODE

#!/bin/bash
tar -cvf backup.tar /home/kian/
echo "Backup Created Successfully!!! :D"

Don't forget to put your text between quotes!

Is there a way to put comments so that the script will be more readable by users? Yes! you just have to put a "#" mark at the first of the line you want it to be commented. Don't mix it with the "!#" we have at the first line, that one is not for commenting. Here, the completed script looks like this:

CODE

#!/bin/bash
#Creating Tar File - Backing Up User's Directory
tar -cvf backup.tar /home/kian/
#Printing A Sentence On Screen Using Echo
echo "Backup Created Successfully!!! :D"

Finishing It Up!
Now that our script is finished, save the file and issue the following command in Terminal to make the script file executable:

CODE

chmod ugo+x mybackup

To execute the code, write this in Terminal:

CODE

/path/to/script/file/mybackup

Now our script is ready to be used! /cool.gif" style="vertical-align:middle" emoid="B)" border="0" alt="cool.gif" />

Hope this tutorial helped you get started with bash scripting.

Remove System Beep in Linux Tutorials

Anarion — Thu, 05 Nov 2009 16:34:37 -0600

Some people (including myself) hate that nasty beep, when it starts to sound, I start to get a headache. Is there a way to remove it? Yes and it's quite easy. Just to the following:

(you can use gedit or any editor of your choice instead of vim)
1. if you want to disable the beep temporarily (until the next startup)

CODE

sudo rmmod pcspkr

Go and check, it is gone!!! /biggrin.gif" style="vertical-align:middle" emoid=":D" border="0" alt="biggrin.gif" />

2. if you want to disable it forever (until you enable it again)

CODE

sudo vim /etc/modprobe.d/blacklist

then add this line in the file:

CODE

blacklist pcspkr

now save the file and from the next reboot, you won't hear it again.

3. another way to disable it forever (until enabling it again)

CODE

sudo vim /etc/inputrc

now, look for the line where it says "set bell-style audible", change it to one of these:

CODE

set bell-style visible
#or
set bell-style none

save and reboot and /biggrin.gif" style="vertical-align:middle" emoid=":D" border="0" alt="biggrin.gif" /> it is gone.

Hope this tutorial helped you get free of the annoying beep when you work with system. /wink2.gif" style="vertical-align:middle" emoid=";)" border="0" alt="wink2.gif" />

Hash Table and It's Usage in C++ Tutorials

Anarion — Tue, 03 Nov 2009 02:58:43 -0600

Hi! this is my first tutorial and I'm going to explain how hashing and hash table works and how to use it. OK, but what is Hash Table actually and how can it benefit us? well, a Hash Table is a type of table in which we can use each record's id to retrieve the it's data easily. So, each record must have a unique id, which is going to be an int higher than or equal to 1. And another thing to mention, we use a value of -1 for id for each empty record's id.

Hash Function
For this tutorial, I used the following simple function to hash a given id:

hash(id) = id%size;

size is the length of our table, which has to be a prime number. I used 51 in this tutorial. The reason why it needs to be prime is that, if we don't use a prime number, the resulting hashed value will be zero for each id divideable by size. But if we use a prime number for size, then we decrease the chance of id being divideable by size.

Collisions

When inserting items into a hash table, it sometimes happens that an item to be inserted in table has a hash value that points to an already existing location in table. The new item typically is inserted somewhere else, though we must be sure that there is still a way to look up the item.

One of the simplest ways to overcome collisions is to use a rehash function:

rehash(id) = (id+1)%size;

Note: When we hash an id and check and see that it is already taken, we give the hashed id to rehash function.

OK, now here's an example program I wrote to implement a hash table and function. It's quite straight forward but I commented it too:

CODE

#include <iostream>
#include <string>
using namespace std;

//data structure to hold id and data, our data-structure we want to use
struct data {
public:
        int id; //to hold a unique id for each element
        int data; //the data for each element, I used a simple int
};

class hasher {
        data dt[51]; //the table to hold hashed data structs
        int numel; //number of elements in table, to check if it's full
public:
        hasher();
        int hash(int &id);
        int rehash(int &id);
        int add(data &d);
        int remove(data &d);
        void output();
};

/*this is the function to give hashed id, it's a simple one...
It's better that we use a prime number for our length, thats why I used 11
and the bigger possible, it's better because we reduce our collisions*/
int hasher::hash(int &id) {
        return (id%51);
}
/*in case of ay collision(a hashed value which is already occupied before)
we use rehash function instead of hash*/
int hasher::rehash(int &id) {
        return ((id+1)%51);
}

hasher::hasher() {
        //create an array of data structure
        int i;
        for(i=0;i<=50;i++) {
                dt[i].id = -1; //set all ids to -1 to show they're empty
                dt[i].data = 0; //set all data values to 0, which is default
        }
        numel = 0;
}

int hasher::add(data &d) {
        if(numel < 51) {
                //table has empty places...
                int hashed = hash(d.id);
                if(hashed >= 0 && hashed <= 50 && dt[hashed].id == -1) {
                        //slot is empty, assign new data
                        dt[hashed].id = d.id;
                        dt[hashed].data = d.data;
                        return 0;
                } else {
                        //we need to rehash the id
            int i=0;
            //try every place in table to find an empty place
            while(i<=50) {
                            hashed = rehash(hashed);
                            if(dt[hashed].id == -1) {
                                    dt[hashed].id = d.id;
                                    dt[hashed].data = d.data;
                                    return 0;
                            } else if(i==50) {
                                    //we couldn't find the empty place
                                    return -1; //terminate function with error
                            }
                i++; //update value of i
            }
                }
        } else {
                //table is full
                return (-1);
        }
}

int hasher::remove(data &d) {
        int hashed = hash(d.id);
        if(dt[hashed].id == d.id) {
                //this is the right one to delete
                dt[hashed].id = -1;
                numel -= 1;
                return 0;
        } else {
                //we need a rehash to find the one
        int i=0;
        while(i<=50) {
                    hashed = rehash(hashed);
                    if(dt[hashed].id == d.id) {
                            dt[hashed].id = -1; //set the id to -1 because it is going to be empty
                            numel -= 1; //decrease 1 from number of elements
                            return 0; //success
                    } else if(i==50) {
                            return -1; //terminate function
            }
            i++; //update the value of i
                }
        }
}

void hasher::output() {
        int i;
        for(i=0;i<51;i++) {
                cout<<i<<" ->  "<<dt[i].id<<"     "<<dt[i].data<<endl;
        }
}

int main() {
        int id=45; //first id
        int ret;
        data d;
        d.data = 52005; //a value for all records, simply
        hasher h1;
        while(ret != -1) {
                d.id=id;
                ret = h1.add(d); //add this record to table
                id += (id/5); //update the id, I wanted to show how different ids are put in table, look at output
        }
        d.id = 271861; //set to one of the ids we added to table in above loop
        h1.remove(d); //remove that record from table
        h1.output(); //see the output, notice there is one empty record, in index number 33, that was the record with id of 271861
        return 0;
}

Final Thoughts

In this tutorial, I used a simple hash function which was good enough for working with integer values, but what if we want to hash strings ? Yup we need a more advanced function to do that. There are many ways to do that which is beyond this tutorial's goals. But at least you are now familiar with the way hashing works. Hope this tutorial helped you! /biggrin.gif" style="vertical-align:middle" emoid=":D" border="0" alt="biggrin.gif" />

wxWidgets: Threading and using the Clipboard in C++ Tutorials

gabehabe — Sat, 31 Oct 2009 12:05:58 -0500

wxWidgets: Threading, and using the Clipboard

Two for one in this tutorial. We're going to create a thread using wxWidgets, and make it monitor the clipboard for text. Then, if we detect a change, we're going to add the new contents to a list.

It's a relatively simple process, but unfortunately wxWidgets isn't the most documented GUI toolkit out there.

So, let's get started. I'm gonna pile all the code into a single file instead of breaking my classes up into seperate files, just for ease of navigation in this tutorial. The code is relatively short anyway, with only 62 lines.

First off, as with any other program, we're going to want to get our includes done. We'll be needing three: The standard wx header, the clipboard header, and the thread header.

CODE

#include <wx/wx.h> // standard wx header
#include <wx/clipbrd.h> // clipboard - we'll monitor the clipboard for text
#include <wx/thread.h> // include threads!

The next thing we need to do is declare our [il]ClipLogger[/il] class - this will inherit wxThread, and have two variables: One to hold the most recent text that we got from the clipboard, and one which is a pointer to a [il]wxListBox[/il] object -- the object on the main window which we'll be updating.

CODE

class ClipLogger : public wxThread {
    public:
        ClipLogger(wxListBox*);
    private:
        void* Entry(); // the entry point to the thread

        wxString LatestText; // store the last text so we can check for changes
        wxListBox* list; // the list to update on a text change
};

The constructor is very simple. All it does is take a wxListBox*, and assign it to a variable stored by the class - this is the list that we want to update on clipboard text changes.

CODE

ClipLogger::ClipLogger(wxListBox* l) {
this->list = l;
}

Next up is the main part of this tutorial. When we create a thread, we need to override the [il]Entry()[/il] method of the class, like so:

CODE

void* ClipLogger::Entry() {

To save time and memory, rather than creating a variable every time we loop, we'll create it before and simply overwrite it inside the loop.

CODE

wxTextDataObject temp;

wxTextDataObject is the type of object that the clipboard will store.
Next, since our thread is a constant "monitor" for the clipboard, we want it to loop.

CODE

while (true) {

Then, we need to think about how we can help our application not be CPU-hungry. The simple solution is to make the thread sleep each time it loops. We can do this with [il]wxSleep(int time)[/il], where time is the length of time to sleep in seconds.

CODE

wxSleep(1);

The rest of the loop is the clipboard. It's very simple, so rather than break it up line-by-line, I've added comments along the way. We basically need to do the following:
- Open the clipboard
- If the clipboard is text, get it into our [il]temp[/il] variable
- Update the list and remember this is the most recent (so as not to constantly add the same data to the list)
- Close the clipboard

CODE

        if (wxTheClipboard->Open()) { // try to open the clipboard
            if (wxTheClipboard->IsSupported(wxDF_TEXT)) { // if the clipboard contains text
                wxTheClipboard->GetData(temp); // get the data from the clipboard
                if (this->LatestText != temp.GetText()) { // if it's changed, we want to update
                    if (temp.GetText() != wxT("")) { // if it's not an empty string
                        this->LatestText = temp.GetText();  // update the "LatestText"
                        this->list->Append(temp.GetText()); // append to the list
                    }
                }
            }
        }
        wxTheClipboard->Close(); // close the clipboard

The last thing left to do in the thread is simply close it off, and close off the loop.

CODE

}
}

Simple, huh? /smile.gif" style="vertical-align:middle" emoid=":)" border="0" alt="smile.gif" />

And that's our thread defined. Now all we need to do is create the app itself, which is a simple process. I hope that you already know how to do it, so we can blitz through the majority of it. If not, you may want to review this tutorial.

Create the app:

CODE

class threaded_app : public wxApp {
public:
bool OnInit(void);
};

The beginning of the [il]OnInit()[/il] should be nothing new at this point either.

CODE

bool threaded_app::OnInit(void) {
    // quickly create a wxFrame to display a window
    wxFrame* f = new wxFrame(NULL, wxID_ANY, wxT("Threaded App!"));

    // add a list to the frame we created
    wxListBox* list = new wxListBox(f, wxID_ANY);

    // display the frame
    f->Show(true);

The last part of [il]OnInit()[/il] that we need to do is actually create an instance of our thread and run it, like so:

CODE

    // pass the list to the clipboard monitor so it knows what to update
    ClipLogger* cl = new ClipLogger(list); // construct our thread
    cl->Create(); // we have to create a thread before we can run it
    cl->Run(); // run our thread

And we can simply finish off the [il]OnInit()[/il] and IMPLEMENT_APP:

CODE

return true;
}

IMPLEMENT_APP(threaded_app)

And that's all there is to threading and using the clipboard in wxWidgets!

Here's the complete code:

CODE

#include <wx/wx.h> // standard wx header
#include <wx/clipbrd.h> // clipboard - we'll monitor the clipboard for text
#include <wx/thread.h> // include threads!

class ClipLogger : public wxThread {
    public:
        ClipLogger(wxListBox*);
    private:
        void* Entry(); // the entry point to the thread

        wxString LatestText; // store the last text so we can check for changes
        wxListBox* list; // the list to update on a text change
};

ClipLogger::ClipLogger(wxListBox* l) {
    this->list = l;
}

void* ClipLogger::Entry() {
    wxTextDataObject temp; // create a "wxTextDataObject" to get the info from the clipboard
    while (true) { // our thread will loop
        wxSleep(1); // sleep for 1 second, make the thread less cpu-hungry
        if (wxTheClipboard->Open()) { // try to open the clipboard
            if (wxTheClipboard->IsSupported(wxDF_TEXT)) { // if the clipboard contains text
                wxTheClipboard->GetData(temp); // get the data from the clipboard
                if (this->LatestText != temp.GetText()) { // if it's changed, we want to update
                    if (temp.GetText() != wxT("")) { // if it's not an empty string
                        this->LatestText = temp.GetText();  // update the "LatestText"
                        this->list->Append(temp.GetText()); // append to the list
                    }
                }
            }
        }
        wxTheClipboard->Close(); // close the clipboard
    }
}

class threaded_app : public wxApp {
    public:
        bool OnInit(void);
};

bool threaded_app::OnInit(void) {
    // quickly create a wxFrame to display a window
    wxFrame* f = new wxFrame(NULL, wxID_ANY, wxT("Threaded App!"));

    // add a list to the frame we created
    wxListBox* list = new wxListBox(f, wxID_ANY);

    // display the frame
    f->Show(true);

    // pass the list to the clipboard monitor so it knows what to update
    ClipLogger* cl = new ClipLogger(list); // construct our thread
    cl->Create(); // we have to create a thread before we can run it
    cl->Run(); // run our thread

    return true;
}

IMPLEMENT_APP(threaded_app)

Happy coding! /smile.gif" style="vertical-align:middle" emoid=":)" border="0" alt="smile.gif" />

Intro Generics in Java Tutorials

tivrfoa — Tue, 27 Oct 2009 23:37:36 -0500

This tutorial shows some uses of generics.

Generics and Collections

A non-generic collection can hold any kind of object. Hence, the methods that get objects out of the collection are of the type java.lang.Object.

Suppose you intend to have a list of String�s objects.
Without generics:

CODE

List l = new ArrayList();
l.add(�Dream�);
l.add(�in�);
l.add(�Code�);
l.add(10); // It compiles fine *

// Getting the length of all strings in this list
Iterator i = l.iterator();
while(i.hasNext()) {
String s = (String)i.next(); // cast is needed
System.out.println(s.length());
}

* Pay attention here. I said that compiles fine, but this is true only for Java 5 or above. Java 5 introduced the autoboxing and unboxing features. What the code really does is to insert an Integer object which has the value 10.

This code runs fine, until it tries to cast an Integer to String. So an exception is through at runtime:
Exception in thread "main" java.lang.ClassCastException: java.lang.Integer cannot be cast to java.lang.String

Two great things about generics are that it ensures the type of objects that the collection can have and also eliminates the need to cast. The problem with cast is that it can fails at runtime time. Using generics, this error is caught at compile time.

Now the same code using generics:

CODE

// With generics
List<String> l = new ArrayList<String>();
l.add("Dream");
l.add("in");
l.add("Code");
/*l.add(10); /* It won't compile.
        Error: generics\Test1.java:33: cannot find symbol
        symbol  : method add(int)
        location: interface java.util.List<java.lang.String>
            l.add(10); // Won't compile. Error:
        */

// Getting the length of all strings in this list
for(String s:l) {
    System.out.println(s.length());
}

Remove the �/*� before l.add(10); to generate the compile error.

You can easily use generics for parameter and return types. The following examples illustrate this.

CODE

public List<String> getList() {
return new ArrayList<String>();
}

public void setList(List<String> list) {
myList = list;
}

Ok. Those were the basic uses of generics. Let�s see other interesting things.

Legacy Code

The following code will compile:

CODE

List<String> l2 = new ArrayList<String>();
l2.add("Dream");
l2.add("in");
OldClass oc = new OldClass();
oc.insert(l2); // No compile error and no exception
for(String s:l2) { // ClassCastException
    System.out.println(s.length());
}

class OldClass {
    public void insert(List list) {
        list.add(new Integer(10));
    }
}

In order to support legacy code, Java 5 and Java 6 allows your newer type safe code to make use of older code. So code above compiles, even passing an Integer object to a list of String. The exception only happens when you try to cast from Integer to String.

Polymorphism

Polymorphism doesn�t apply for generics.
Eg:

CODE

class Animal {}
class Dog extends Animal {}
List<Animal> list = new ArrayList<Dog>();

Error:
incompatible types
found : java.util.ArrayList<generics.Dog>
required: java.util.List<generics.Animal>
List<Animal> pList = new ArrayList<Dog>();

So, in the below method, the only thing you can pass as parameter is List<Animal>.

CODE

public void add(List<Animal> animals) {}
List<Dog> dogs = new ArrayList<Dog>();
add(dogs); // error

? wildcard

You can use the wildcard �?� to partially solve the above problem.

CODE

public void add(List<? extends Animal> animals) {}
List<Dog> dogs = new ArrayList<Dog>();
add(dogs); // OK!! :)

But you can�t really add something to the list, not even an Animal.

CODE

public void add(List<? extends Animal> animals) {
animals.add(new Animal()); // very awkward error :(
}

The extends keyword can also be used with interfaces (in this case!).
public void add(List<? extends Runnable> list) {}

Another Java keyword has a special meaning in generics: super.

CODE

public void add(List<? super Dog> dogs) {
dogs.add(new Dog());
}

It means that you can pass a Dog or a supertype of Dog. Note that you can only add a Dog!

Conclusion

This was a simple introduction. I recommend you to make a search to learn some tricks and advanced techniques.

Reference
Sierra, Katherine; Bates, Bert. SCJP Sun Certified Programmer for Java 6.
http://www.amazon.com/SCJP-Certified-Progr...5/dp/0071591060
It�s an AMZING BOOK!!!

Highlight and search words in page in PHP Tutorials

noorahmad — Sat, 31 Oct 2009 01:06:51 -0500

QUOTE

Excellent tutorial! Keep up the great work

Thanks /smile.gif" style="vertical-align:middle" emoid=":)" border="0" alt="smile.gif" />, I will try my best.

Create own User control - Basic Steps. in Visual Basic Tutorials

Vineeth k — Mon, 26 Oct 2009 04:05:14 -0500

Hello friends here , i made a simple and Basic steps to learn how to create your own controls.I think it is very useful when you create your own controls.This post covers only basic steps to create a new control which will show images with their file id and if there is no image It will show No image. This is not a perfect one but it will help you to crate own controls with custom properties.

First start a new project in vb then select Project Explorer , normally top of the properties.Right click on the Project 1 and select Add - User control.Here you can create new or open existing Controls. Now click new User-control.
It is just like a vb form ,you can add buttons , labels , anything you need like a normal form.
When you added a new user-control then you can see it in tools.
To get your control then close the User-control then open the first form , now add your control form the tools.Please remember that it will not work if you open the User-control.Here i made normal References , nothing more ...
Create Own User Control :

Close all forms and controls , open the new User-control ..

Add one image control ,change its properties to :
Name = img
Height = 500
Width = 2000
Stretch = True
Add one Label
Name =lbl
Autosize =false
BackStyle =0-Transparent

Changing name of user-control:
Just change the name property like a form.Set it to MyImage.If you add your controlto your form then it will appear like MyImage1.

The first and important part of a user-control is its properties , events and Methods.It is easy to create all.But the first thing to change is its Initialize and Resize.To do this Double click on the user-control then in code add this :

CODE

Private Sub UserControl_Initialize()
UserControl.Height = 500
UserControl.Width = 2000
End Sub

Private Sub UserControl_Resize()
img.Width = UserControl.Width
img.Height = UserControl.Height
lbl.Width = UserControl.Width
lbl.Height = UserControl.Height
End Sub

Here Initialize is like form load.Every code in Initialize works on when you create a new user control.
Resize will work when you change the size of user-control.Here i used code to adjust the height and width of image control and label control when the user change the size of the control.Else if the user change the size of the control then it will become a disorder.
After that you can set its properties.Properties are visible in the properties window , it will allow users to access any part of the control like setting the control enable or disable or changing the caption.You can access the property of a control in coding.

To create a new Property :
In code view In menu bar : Take tools and click Add Procedures , then select Property [ it will create a new property ] and type " Caption " in that box.
Then you will get this

CODE

Public Property Get Caption() As Variant

End Property

Public Property Let Caption(ByVal vNewValue As Variant)

End Property

Here it will set a Property called caption like Label caption.Using this property you can use it to do what you think.Here i am using this property to display the caption of the Label - lbl and load that image file id to the image control - img.
For this add these lines :

CODE

Public Property Get Caption() As Variant
Caption = lbl.Caption
End Property

Public Property Let Caption(ByVal vNewValue As Variant)
lbl.Caption = vNewValue
PropertyChanged "Caption"
End Property

Here it will change the caption of the label when you typed a text in the caption property of the user control. [do it in form view , after closing the control]You can use the property like normal label : UserControl11.Caption = "Button Click"
But the new property Caption is a temporary , if you run the program the caption will change back.To stop this just change the user-control 's WriteProperties & ReadProperties.Now in code view add this :

CODE

Private Sub UserControl_WriteProperties(PropBag As PropertyBag)
PropBag.WriteProperty "Caption", lbl.Caption
End Sub

Private Sub UserControl_ReadProperties(PropBag As PropertyBag)
lbl.Caption = PropBag.ReadProperty("Caption", lbl.Caption)
End Sub

Now the caption will become permanent.If you want to add image to your image control then Change the Caption and ReadProperties code to this

CODE

Public Property Get Caption() As Variant
Caption = lbl.Caption
End Property

Public Property Let Caption(ByVal vNewValue As Variant)
On Error Resume Next
lbl.Caption = vNewValue
PropertyChanged "Caption"
img.Picture = LoadPicture(lbl.Caption)
End Property

Private Sub UserControl_ReadProperties(PropBag As PropertyBag)
On Error Resume Next
lbl.Caption = PropBag.ReadProperty("Caption", lbl.Caption)
Set img.Picture = LoadPicture(lbl.Caption)
End Sub

Now it will load image when you give the file id to your caption.If it is a wrong file name then nothing will happen , for that i am used On Error Resume Next.Now you can change the image of the control at run time just call the Caption property and give a value.

Adding a method will help you to do more works in user-control in form or at run-time.If you want to add a new method then use this codes:
Take tools and click Add Procedures , then select Sub [ it will create a new method ]Type " check " in that box.The result will be :

CODE

Public Sub check()
If img.Picture = False Then lbl.Caption = "No Image"
End Sub

Here i used a new method to check that the image contains any image or not.The real use of such methods appear when you need to check it at run time.For calling one method open form add a button and in code view just add one line like this : UserControl11.check , the result will be " No Image " . When you run the program and click the button then it will call the method.
Adding an event
Events appear when you double click them or selecting from a combo [ top side in the code view].Events are used to do action when the user did something. for example Click event , it will activate the code in that event when you click that control.Adding an event is like adding a new method .To Add a new event :
Take tools and click Add Procedures , then select Event [ it will create a new method ]
Then you will get : Public Event Click()
Add this to your code.It will call the click event when user clicks the label or control.

CODE

Private Sub lbl_Click()
RaiseEvent imgClick
End Sub

Private Sub UserControl_Click()
RaiseEvent imgClick
End Sub

To access the new event , close all forms and controls , open the first form, and add one new control and double click it then you can see the new event imgClick.
Like click you can add any event for your control.To make your control more useful it is necessary to create more properties like Enable , setting font ....You can add any properties you like but the important thing is you must change it or add codes in ReadProperties & WriteProperties.

Enable \ Disable : Allow you to make a control enable or disable.

CODE

Public Property Get Enabled() As Boolean
    Enabled = m_bEnabled 'declare m_bEnabled before Private m_bEnabled As Boolean
End Property
Public Property Let Enabled(ByVal New_Enabled As Boolean)
    m_bEnabled = New_Enabled
    UserControl.Enabled = m_bEnabled
    PropertyChanged "Enabled"
End Property

Font : will change the font of the caption.

CODE

Public Property Get Font() As StdFont
    Set Font = UserControl.Font
End Property

Public Property Set Font(ByVal New_Font As StdFont)
    Set UserControl.Font = New_Font
    Set lbl.Font = New_Font
    Refresh
    PropertyChanged "Font"
End Property

Change the ReadProperties & WriteProperties to make the property working.

CODE

Private Sub UserControl_ReadProperties(PropBag As PropertyBag)
On Error Resume Next
lbl.Caption = PropBag.ReadProperty("Caption", lbl.Caption)
Set img.Picture = LoadPicture(lbl.Caption)
    With PropBag
        Set UserControl.Font = .ReadProperty("Font", Ambient.Font)
        Set lbl.Font = .ReadProperty("Font", Ambient.Font)
        m_bEnabled = .ReadProperty("Enabled", True)
        UserControl.Enabled = m_bEnabled
    End With
End Sub

Private Sub UserControl_WriteProperties(PropBag As PropertyBag)
PropBag.WriteProperty "Caption", lbl.Caption
PropBag.WriteProperty "Caption", lbl.Caption
    With PropBag
        .WriteProperty "Enabled", m_bEnabled, True
        .WriteProperty "Font", UserControl.Font, Ambient.Font
    End With
End Sub

You can make the control enable or disable and change the font of the caption
The full code i used to create this control is given.[attachmentid=14551]

Best Of Luck ...

Twitter Logo Remake In Photoshop [Regular + Halloween] in Graphic Design & Photoshop Tutorials

Master Jake — Tue, 20 Oct 2009 19:40:26 -0500

Here's the final result of the logo we will be making today:

And here is my Halloween version:

First off, you need to find a font that you would like to use. I generally use the font known as "Tondo" because it resembles the actual font of the twitter logo very closely.

You can download Tondo here: http://www.dafont.com/tondo.font

Install it (or whatever font) on Windows XP by opening up Control Panel -> Fonts, and then dragging the font over into the Fonts folder. On vista, simply right-click the font and select "Install."

Once you have your font ready, open up Photoshop. Your document should be properly sized to fit the logo but not too big as to leave empty space. I will be using the size [inline]350x125[/inline] pixels. Resolution 72 pixels per inch. Color mode RGB, 8 bit. Background contents white (we will change this later). Just the default settings pretty much.

Now that we have our open document, let's start off by unlocking the background layer (just in case). To do this, ALT+Double Click the name of the layer.

Now, let's create a new layer using the New Layer icon or by pressing CTRL+ALT+SHIFT+N.

Go ahead and select the text tool, select the Tondo font (or whatever font you are using), set the size to about 72 points, and type out the word "twitter" (or whatever text you wish to type). Yes, leave the 't' lowercase.

Your stage should now look like this:

There is a small adjustment we need to make to the text's character spacing. I've noticed the twitter logo seems to have the characters pretty close together. After some experimentation, I find that [inline]-60[/inline] character tracking works best for the font size 72 points.

To change this, go to Window -> Character. On the window that pops up, find Character Tracking, and set it to -60. Character tracking is the text highlighted in the screenshot below. While your in the character panel, go ahead and change the text color to whatever you like. I will be using the twitter logo's exact color which is hex code [inline]#33ccff[/inline].

Now, select the background layer (the layer we unlocked earlier), set your foreground color to solid black by pressing the "D" key on your keyboard to restore default colors, or just clicking the foreground icon and changing it in the color panel. Now, press ALT+Backspace to fill the layer with black. We are doing this right now so that we can see the white stroke we are about to apply to the text.

Your stage should now look like this:

Alright, now select the layer with our text on it, and go to Layer->Layer Style->Blending Options. Check the box next to "Stroke". Now, we need to find a decent size for our stroke. I find that for font size 72 point, the stroke size of [inline]8[/inline] works perfectly. Change the fill color to solid white (#FFFFFF).

Now, your logo is almost done. This last step is optional, but I think it adds a bit more style to the logo.

First, CTRL+Click the icon of the text layer. This will make a complete selection around the next. Next, create a new layer above the text layer. Select the elliptical marquee (you may have to click and hold down the rectangular marquee tool until a list pops up and the select the elliptical from the list). Hold SHIFT+ALT, click a bit off the stage in the top left hand corner, then hold and drag to off the stage a bit in the right hand corner. Let go of the mouse and you should have created a new, oval like selection at the top of the text.

Select the gradient tool by clicking down and holding on the fill tool (the bucket) until a last comes down, then selecting the gradient. Change your foreground color to solid white (#FFFFFF) and change the gradient settings to Foreground to Transparent by clicking on the gradient in the upper left hand corner of the screen under the "Edit" and "Image" drop-down buttons, then selecting Foreground to Transparent from the list (the second icon on the list).

Hold down SHIFT and click and hold a bit above the text. Drag your mouse down to a bit below the text and let go of the mouse. This will make a nice highlight on the text. You may need to experiment around with where you click and where you let go for best results. Now, if needed, drop the opacity of the new layer with the highlight on it down a bit. Sometimes I find 60% opcaity best, sometimes 40%, and sometimes I don't change the opacity at all. It really depends on where you clicked and let go of the mouse during the gradient stage on how intense the gradient is and where it fades out.

Here is what the stage should look like:

Now, if you wish to have a transparent background, click the eyeball next to the background layer to turn it off. Thank you for reading my tutorial. I hope it gave you new insight into photoshop and helped you create a cool logo. You can change the text of the logo to whatever you like and experiment around with the colors and settings to create new and cool logos (like the Halloween version I created).

Again, here is the final result of the logo:

Password Reset System Without Using A Database in PHP Tutorials

Master Jake — Tue, 20 Oct 2009 18:07:22 -0500

NOTE: "Without Using A Database" means we aren't going to be storing keys in the database, not that we won't be using one period. We will need a database with user's in them; otherwise, resetting passwords is pretty pointless.

This tutorial is going to be on a password reset system to go with your registration/login systems. People forget their passwords often, so it is a good idea to create a system allowing them to reset their password when needed.

Now, there are a couple ways to go about doing this. One is without the use of a database, and one is with the use of a database. Obviously, we are going to be going over the one without the use of a database today.

The negative end of this is that each user's unique password reset key will always be the same. This being the case, this key should be protected even more than the password itself. I recommend telling the user's that when you e-mail them the key. If they are to give out their unique key to someone (as well as their e-mail address), anyone will be able to reset their account password at any time.

The positive end of actually using a database is the exact opposite of the negative end of not using one. When using a database, you can also generate a unique key for each user which is only good for one password recovery. This is much more secure as even if a user does give out his/her key, the password can only be reset once using that key. If a user's account is stolen, he/she can simply reset the password again which will send them a new unique key. They can use this new unique key to reset their password and then their account is safe again.

However, as stated, we aren't going to be using the database approach today.

Now, there are a few things this password reset system depends on:

1. PHP mail() function must be enabled
2. You must have each user's e-mail stored in a database in order for us to mail them their password

If you are ready, let's get started.

/smile.gif" style="vertical-align:middle" emoid=":)" border="0" alt="smile.gif" />

First of all, we will use 2 pages for this complete system. I will only be posting the important snippets of each page such as the form and PHP script. We'll call these 2 pages forgot_password.php and reset_password.php

Let's start with forgot_password.php. We need to create a form which asks for the user's e-mail. The action of the form will be $_SERVER["PHP_SELF"] so that it returns to the same page the form is on to process the information. We will use PHP at the top of this page to process the form, create the unique user key, and then send it to them via e-mail.

Let's do the form first:
forgot_password.php

CODE

<form action="<?php echo $_SERVER["PHP_SELF"]; ?>" method="post">
E-mail Address: <input type="text" name="email" size="20" /> <input type="submit" name="ForgotPasswordForm" value=" Process " />
</form>

Alright. We have a text field called "email" and a submit button called "ForgotPasswordForm." The submit button is named so that we can check to see if the right form was submitted.

Now let's get onto the PHP code for this page:
forgot_password.php

CODE

<?php

// Connect to MySQL
$c = mysql_connect("localhost", "root", "");
mysql_select_db("main", $c);

// Was the form submitted?
if ($_POST["ForgotPasswordForm"])
{
    // Harvest submitted e-mail address
    $email = mysql_real_escape_string($_POST["email"]);

    // Check to see if a user exists with this e-mail
    $userExists = mysql_fetch_assoc(mysql_query("SELECT `email` FROM `users` WHERE `email` = '$email'"));
    if ($userExists["email"])
    {
                // Create a unique salt. This will never leave PHP unencrypted.
                $salt = "PiuwrO1#O0rl@+luH1!froe*l?8oEb!iu)_1Xaspi*(sw(^&.laBr~u3i!c?es-l651";

        // Create the unique user password reset key
        $password = md5($salt . $userExists["email"]));

        // Create a url which we will direct them to reset their password
        $pwrurl = "www.yoursite.com/reset_password.php?q=" . $password;

        // Mail them their key
        $mailbody = "Dear user,\n\nIf this e-mail does not apply to you please ignore it. It appears that you have requested a password reset at our website www.yoursitehere.com\n\nTo reset your password, please click the link below. If you cannot click it, please paste it into your web browser's address bar.\n\n" . $pwrurl . "\n\nThanks,\nThe Administration";
        mail($userExists["email"], "www.yoursitehere.com - Password Reset", $mailbody);
        echo "Your password recovery key has been sent to your e-mail address.";
    }
    else
        echo "No user with that e-mail address exists.";
}

?>

Quite a bit is going on here, so let's break it down into sections and I'll explain what each is doing.

CODE

<?php

// Connect to MySQL
$c = mysql_connect("localhost", "root", "");
mysql_select_db("main", $c);

We start by connecting to MySQL so that we can check to see if a user exists with the submitted e-mail, etc. The host, username, password, and database name may be different for your account. You should know your MySQL settings.

CODE

// Was the form submitted?
if ($_POST["ForgotPasswordForm"])
{

Here we are just checking to see if the form was submitted. If the post value of ForgotPasswordForm (the name of our form's submit button) is true, then the form was submitted.

CODE

// Harvest submitted e-mail address
$email = mysql_real_escape_string($_POST["email"]);

Here we are retrieving the e-mail submitted from the form and MySQL_Real escaping it. This is so that when we check it with the database, it won't contain harmful characters which can be used for SQL Injection. (Hackers are terrible people)

CODE

// Check to see if a user exists with this e-mail
$userExists = mysql_fetch_assoc(mysql_query("SELECT `email` FROM `users` WHERE `email` = '$email'"));
if ($userExists["email"])
{

These lines of code are interesting. We are creating a variable called "$userExists" which will actually become an associative array from mysql_fetch_assoc(). Basically, it is running a query saying, "Select the user's e-mail address from the table `users` where their e-mail address is equal to the one submitted."

Why are we doing this exactly? Well, to check to see if the user really does exists, of course. The fields in the query will change depending on your database, but I'm sure you already knew that. The next if statement checks to see if [inline]$userExists["email"][/inline] has a value. If it does, then we know the user exists (because the query returned a value into the variable).

CODE

// Create a unique salt. This will never leave PHP unencrypted.
$salt = "PiuwrO1#O0rl@+luH1!froe*l?8oEb!iu)_1Xaspi*(sw(^&.laBr~u3i!c?es-l651";

You may be wondering what this is. Well basically, it's a SALT. Now what is a SALT? It's a key of random letters, numbers, digits in general, characters, whatever you want to call it. It's basically a key that never leaves your PHP code. You do not store your salt in a database, print it to the screen, or ANYTHING without it being encrypted. It also needs to be long and very random so that it is very difficult to figure out what the salt really is when it is encrypted.

CODE

// Create the unique user password reset key
$password = md5($salt . $userExists["email"]));

This line makes use of the SALT. Basically we are saying, add the SALT together with the user's e-mail address and then hash it with MD5. If the user entered say "blahman@yahoo.com" for his e-mail address, the salt combined with that would become:

[inline]PiuwrO1#O0rl@+luH1!froe*l?8oEb!iu)_1Xaspi*(sw(^&.laBr~u3i!c?es-l651blahman@yahoo.com[/inline]

Now, when we hash this entire new combined string in MD5, it becomes secure. You will see later how we use this key to actually check and reset the password.

CODE

// Create a url which we will direct them to reset their password
$pwrurl = "http://www.yoursite.com/reset_password.php?q=" . $password;

Here we are creating a url and storing it in the variable "$pwurl." You don't have to store it into a variable and can actually put in the mail string itself, but I did this so it would be easier to point out and explain.

You basically need the URL to point your websites "reset_password.php" page that we talked about earlier in this tutorial. We are also adding "?q=" to the end of it and appending the user's new password key onto it. This way, we can check the URL on the "reset_password.php" page to get the user's key when they click the link from their e-mail.

CODE

// Mail them their key
$mailbody = "Dear user,\n\nIf this e-mail does not apply to you please ignore it. It appears that you have requested a password reset at our website www.yoursitehere.com\n\nTo reset your password, please click the link below. If you cannot click it, please paste it into your web browser's address bar.\n\n" . $pwrurl . "\n\nThanks,\nThe Administration";
mail($userExists["email"], "www.yoursitehere.com - Password Reset", $mailbody);
echo "Your password recovery key has been sent to your e-mail address.";

Here is the long message stored in the variable "$mailbody" which basically tells the user, "hey, if this is you, then click this link and reset your password." You will also see use of the "$pwrurl" variable inside the "$mailbody" string. That is the area where we are placing their password reset link we generated above. Finally, we are using mail() to actually send them the e-mail. We are using "www.yoursitehere.com - Password Reset" as the subject and the value of "$mailbody" as the body message.

CODE

}
else
echo "No user with that e-mail address exists.";
}

?>

Here we are just cleaning up. The else refers to the if statement regarding whether or not the user actually exists. The last curly bracket closes the if statement regarding whether or not the form was actually submitted.

So, now we have created a page which asks the user for their e-mail address; and, if a user exists with that e-mail address, sends them an e-mail with a unique password recovery key for their account. Let's move on to the "reset_password.php" page.

This page is also going to have a form and some PHP code. First we will post the form which, once again, redirects to itself and then processes using PHP. In this form, we need the user to retype his/her e-mail address, new password, and confirm their new password. We also need to store the value of "?q=" from the URL into a hidden section of the form so we can carry it over into processing in post data.

reset_password.php

CODE

<form action="<?php echo $_SERVER["PHP_SELF"]; ?>" method="post">
E-mail Address: <input type="text" name="email" size="20" /><br />
New Password: <input type="password" name="password" size="20" /><br />
Confirm Password: <input type="password" name="confirmpassword" size="20" /><br />
<input type="hidden" name="q" value="<?php echo $_GET["q"]; ?>" /><input type="submit" name="ResetPasswordForm" value=" Reset Password " />
</form>

Now that we have the form for the page, let's move onto the PHP section.

reset_password.php

CODE

<?php

// Connect to MySQL
$c = mysql_connect("localhost", "root", "");
mysql_select_db("main", $c);

// Was the form submitted?
if ($_POST["ResetPasswordForm"])
{
    // Gather the post data
    $email = mysql_real_escape_string($_POST["email"]);
    $password = md5(mysql_real_escape_string($_POST["password"]));
    $confirmpassword = md5(mysql_real_escape_string($_POST["confirmpassword"]));
    $q = $_POST["q"];

    // Use the same salt from the forgot_password.php file
    $salt = "PiuwrO1#O0rl@+luH1!froe*l?8oEb!iu)_1Xaspi*(sw(^&.laBr~u3i!c?es-l651";

    // Generate the reset key
    $resetkey = md5($salt . $email);

    // Does the new reset key match the old one?
    if ($resetkey == $q)
    {
        if ($password == $confirmpassword)
        {
            // Update the user's password
            mysql_query("UPDATE `users` SET `password` = '$password' WHERE `email` = '$email'");
            echo "Your password has been successfully reset.";
        }
        else
            echo "Your password's do not match.";
    }
    else
        echo "Your password reset key is invalid.";
}

?>

Again, a lot is going on here. So let's break it down line by line.

CODE

<?php

// Connect to MySQL
$c = mysql_connect("localhost", "root", "");
mysql_select_db("main", $c);

Connecting to MySQL, again. Nothing new here.

CODE

// Was the form submitted?
if ($_POST["ResetPasswordForm"])
{

Checking to see if the form was submitted.

CODE

// Gather the post data
$email = mysql_real_escape_string($_POST["email"]);
$password = md5(mysql_real_escape_string($_POST["password"]));
$confirmpassword = md5(mysql_real_escape_string($_POST["confirmpassword"]));
$q = $_POST["q"];

This is gathering all of the post data submitted from the form and storing each value into a variable. You may notice the use of mysql_real_escape_string(). Again, we are using this to protect our database from SQL Injection. $q doesn't need to be escaped because we aren't going to be checking it with the database. Also, you may notice use of md5() on the password's. This is because I assume this is the hashing you are using on your passwords. Change it if needed.

CODE

// Use the same salt from the forgot_password.php file
$salt = "PiuwrO1#O0rl@+luH1!froe*l?8oEb!iu)_1Xaspi*(sw(^&.laBr~u3i!c?es-l651";

Here we are, once again, creating the salt. Make sure this is the EXACT same salt you used from the forgot_password.php file or the system won't work.

CODE

// Generate the reset key
$resetkey = md5($salt . $email);

As we did in the forgot_password.php file, we are combining the salt and the user's inputted e-mail and then hashing it with md5(). We are storing it into a variable called $resetkey this time.

CODE

// Does the new reset key match the old one?
if ($resetkey == $q)
{

This is the major check. Since we combined the same salt with the same e-mail and hashed it the same way, both $resetkey and $q will be the same. If they aren't the same, the user either inputted the wrong e-mail address or it's a hacker trying to steal their account.

CODE

if ($password == $confirmpassword)
{

This is making sure both the password and confirmed password match.

CODE

// Update the user's password
mysql_query("UPDATE `users` SET `password` = '$password' WHERE `email` = '$email'");
echo "Your password has been successfully reset.";

Here we are simply running a mysql_query() to update the user's password and set it to the new one where their e-mail equals the one submitted. Afterward, we are echoing out that it has been successful. Again, you may need to change the table `users` and the fields depending on your database.

CODE

}
else
echo "Your password's do not match.";
}
else
echo "Your password reset key is invalid.";
}

?>

This is all the clean up and finalizing code. We are running else statements on previous if's. The first one is for whether or not the password and confirmed password matched. If not, tell them it didn't. The second is for the check determining whether or not the new recovery key matched the old one. The final curly braces closes the if statement which checked to see if the form was actually submitted.

CONGRATULATIONS!

If you have made it this far, your password reset system is complete. I hope my tutorial has helped you learn and understand new concepts. Go out and enjoy the wonderful world of PHP now!

Search Engine [Basic] in PHP Tutorials

Master Jake — Tue, 20 Oct 2009 11:48:32 -0500

Hello. Today you are going to be learning how to create a very simple search engine system which you can implement into your own website. Keep in mind that this search engine tutorial is meant to teach only the fundamental basics.

If you are implementing this search engine into a professional or commercial site, be sure to update it with paging so that 20 billion results aren't displayed on one page. Let's get started.

1: The Database

In order for this search engine to operate properly, we need to store information into a database which we will scan for later. You can use this to search pretty much any field in a table; however, for this example we will be using a simple "blog" type section.

Our database will be very simple, and looks like this:

CODE

TABLE: blog_entries

id (primary key; auto increment) - int(11)
blogbody - text

Obviously, a real blog_entries table would contain MUCH more data than this;however, like I said, I want to make this as simple and easily understandable as possible.

Now, we will assume that there are already quite a few entries into this table for which we may search.

First, we need to create an HTML form field using GET as the method so that our user's can search the database.

File: test.html

CODE

I didn't name the input for the submit button because it's not really needed for this example.

Now, there are a few things you may notice. First of all, this form directs the data to the page "search.php" using the "get" method. This means that if the user type's in say "Hello World" in the input textbox and press's "Search", the url will look like this:

CODE

search.php?q=Hello+World

The nifty thing about using the get method is that it will automatically url encode the form data and then url decode it when we use php's $_GET to retrieve it.

Speaking of PHP, let's get on with the "search.php" page which this form directs to.

First we need to connect to MySQL so that we can use mysql_query and etc.

CODE

<?php

$c = mysql_connect("localhost", "root", "");
mysql_select_db("my_database", $c);

Of course, the username, password, host, and database name will change depending on your MySQL information. Now that we are connected, let's grab the value of "q" in the URL.

CODE

$q = mysql_real_escape_string($_GET["q"]);
$newq = strtoupper($q);

We use mysql_real_escape_string to escape harmful characters which can be used to SQL Inject the database. We also created a second variable called "$newq" which is simply an all uppercase version of the search query. This is that we may run a case insensitive search.

Now that we have the information in which the user submitted (and keep in mind that $_GET automatically url decoded the data), we may run the main search query.

CODE

$searchQuery = mysql_query("SELECT * FROM `blog_entries` WHERE UPPER(`blogbody`) LIKE '%$newq%' ORDER BY `id` DESC LIMIT 10");

Now, a lot is going on in this query. I hope that if you are reading this tutorial you already know a little about MySQL. First of all, we are selecting every field from the table "blog_entries" (which I showed above). We are selecting only the fields in which the value of "blogbody" contains the string "$newq." We use MySQL's UPPER() around the blogbody so that, once again, the search query is case insensitive. This tests a full uppercase version of the "blogbody" field with a full uppercase version of the search query. All case insensitive.

You may notice the %%'s around $newq. Basically they are wildcards which mean "anything in this spot." This means that if the user searches:

'o'

and the word "dog" is in "blogbody", it will return that result.

%o% = anything-o-anything

dog would match in that case. This is used for better search results. In case the user searches:

tut

instead of "tutorial", it will still match.

You may also notice that we are ordering these by the id descending. Since the id auto increments with each new entry, the highest id is going to be the newest entry. Descending means highest to lowest. Basically we are ordering them from newest to oldest. You can also do this with a date timestamp, but we won't get into that right now.

Also, we are limiting this search to a maximum of 10 results. This is so the page doesn't get cluttered with too many search results. If you want unlimited results, I suggest creating a paging system and adding it to your search system so that it displays say 10 search results per page.

Now that we have the value of the search query tested with the database, we need to print the retrieved values (providing there are any). We can do this by using a while() loop.

CODE

while ($row = mysql_fetch_assoc($searchQuery))
{
echo "Blog Entry #" . $row["id"] . "<br /><br />" . stripslashes($row["blogbody"]) . "<hr />";
}

A few things are going on here. We are assigning the variable "$row" to each row of data retrieved from the search query. Each time the while loop increments, one new row is retrieved and we can print data associated with that row. mysql_fetch_assoc() is simply retrieving the rows and storing them in an associative array of "$row."

These values can be accessed with the variable name, brackets, and the field name in quotes:

CODE

$row["blogbody"]; // returns the blogbody field

The rest is pretty self explanatory. We are echoing out the id of each blog entry that was successfully matched with the search query, and then echoing out the actually blogbody of that field itself. You may notice "stripslashes()" around the blogbody. I assumed that whoever was making the blog system used "mysql_real_escape_string()" to escape the blogbody before entry into the database.

This make's all single and double quotes (and a few other characters) have a backslash before them. E.g. " becomes \". We need to strip those slashes when echoing them out so that \" returns back to ", etc.

Well, that's pretty much it. I hope you found this tutorial helpful, and I hope that it wasn't too confusing. Here is the final code put together:

CODE

<?php

// Connect to MySQL
$c = mysql_connect("localhost", "root", "");
mysql_select_db("my_database", $c);

// Retrieve the Search String
$q = mysql_real_escape_string($_GET["q"]);
$newq = strtoupper($q);

// Run the Search Query
$searchQuery = mysql_query("SELECT * FROM `blog_entries` WHERE UPPER(`blogbody`) LIKE '%$newq%' ORDER BY `id` DESC LIMIT 10");

// Display Results Based on the Retrieved Data
while ($row = mysql_fetch_assoc($searchQuery))
{
echo "Blog Entry #" . $row["id"] . "<br /><br />" . stripslashes($row["blogbody"]) . "<hr />";
}

?>

If you are wondering why I didn't just use "strtoupper" on the "$q" value itself, I wanted it separate so that the original search string was saved. This way, if you wanted to print out what they searched, you could:

CODE

<?php

echo "You searched for <b>" . stripslashes($q) . "</b>";

?>

Installing FLTK for Beginners in C++ Tutorials

balasurfs — Sun, 18 Oct 2009 10:11:15 -0500

Hi, This tutorial is for installing FLTK in your Linux Operating System. i am using Ubuntu jaunty 9.04. You can use this guide to install it in other operating system.

Before installing FLTK in ubuntu or any other Linux distros you need few packages. If you try to install it without these pre-build packages, it will produce an error.

1. You need g++-x.x ( x.x is the version number 3.0+, preferably 4.3 )

You can install this using 'build-essentials'

CODE

ubuntu : sudo apt-get install build-essentials

These essential packages comes with CD rom. All you have to do is add the CD-ROM to software sources.

2. installing autoconf and automake

CODE

sudo apt-get install autoconf automake

3. installing xorg-dev packages and libglut3-dev

CODE

sudo apt-get install xorg-dev libglut3-dev

So the files that needed to be installed are:
1. G++
2. autoconf
3. automake
4. xorg-dev
5. libglut3-dev

In whatever linux distro you are using, use the package manager to install all these. These will also install other dependency files.

Installing FLTK

1. donwload FLTK from their website http://www.fltk.org
2. unrar the package.
3. navigate to the extracted folder in terminal
4. run the following commands in terminal
./configure
sudo make
sudo make install

You are done!.
First fltk Code:

CODE

#include <fltk/Window.h>
#include <fltk/Widget.h>
#include <fltk/run.h>
#include <fltk/ask.h>
using namespace fltk;

void window_callback(Widget* widget, void*) {
  if (ask("Do you really want to exit?"))
    ((Window*)widget)->hide();
}

int main(int argc, char **argv) {
  Window *window = new Window(300, 180);
  window->callback(window_callback);
  window->begin();
  Widget *box = new Widget(20, 40, 260, 100, "Hello, World!");
  box->box(UP_BOX);
  box->labelfont(HELVETICA_BOLD_ITALIC);
  box->labelsize(36);
  box->labeltype(SHADOW_LABEL);
  window->end();
  window->show(argc, argv);
  return run();
}

I got this code from fltk website.

Compiling FLTK program:

In your terminal

CODE

Syntax: fltk2-config --compile <filename.cpp>
$> fltk2-config --compile Apps.cpp
$> ./Apps

Now Fltk is properly installed in you Linux Distro./smile.gif" style="vertical-align:middle" emoid=":)" border="0" alt="smile.gif" />