[joannesablad]

Asak Friends, I'm using Visual C++ 2008 Express Edition and i'm having a linker error in every program that i'm making in it. I'm not able to understand what's the actual problem. I have searched a lot on different blogs or websites. but still i'm unable to understand the linker error LNK2019 and LNK1120 . Here is my code. Help me to solve it!


//stdafx.h header file

#include<iostream>
using namespace std;
template<class T>

int search(T Array[], T key, int size)
{
    for (int i=0; i<size; i++)
    {
        if (Array[i]==key)
        {
            return i;
        }
    return -1;
    }
}

That's the main file.

#include"stdafx.h"
using namespace std;
template<class T>
void main()
{
    char chrArr[] = {'a', 'c', 'f', 's', 'u', 'z'};
    char ch = 'f'; // value to find
    int intArr[] = {1, 3, 5, 9, 11, 13};
    int in = 6;
    double dubArr[] = {1.0, 3.0, 5.0, 9.0, 11.0, 13.0};
    double db = 4.0;
    cout << "\n 'f' in chrArray: index=" << find(chrArr, ch, 6);
    cout << "\n 6 in intArray: index=" << find(intArr, in, 6);
    cout << "\n 4 in dubArray: index=" << find(dubArr, db, 6);
    system("pause");
}

[vividexstance]

Main should return an int and not void. Also, you should never put a using directive (using namespace std;) in a header file. You need to include your header file to be able to use it in the main file.

EDIT: You named the function in your header file "search" but then you call a function "find" three times in main. Did you mean search?

This post has been edited by vividexstance: 23 February 2012 - 10:48 AM

[r.stiltskin]

Quote

#include"stdafx.h"
using namespace std;
template<class T>
void main()
{
// ...

You can't declare main to be a template. Your compiler should be halting at the third line and never get far enough to produce linker errors.

Get rid of that "template ..." line.

[joannesablad]

vividexstance, on 23 February 2012 - 10:47 AM, said:

Main should return an int and not void. Also, you should never put a using directive (using namespace std;) in a header file. You need to include your header file to be able to use it in the main file.

EDIT: You named the function in your header file "search" but then you call a function "find" three times in main. Did you mean search?

Ok. After Fixing, what you have said. i'm still having the same problem linker error..

 #include<iostream>
template<class T>

int search(T Array[], T key, int size)
{
    for (int i=0; i<size; i++)
    {
        if (Array[i]==key)
        {
            return i;
        }
    return -1;
    }
}

 #include"stdafx.h"
using namespace std;
template<class T>
int main()
{
    char chrArr[] = {'a', 'c', 'f', 's', 'u', 'z'};
    char ch = 'f'; // value to find
    int intArr[] = {1, 3, 5, 9, 11, 13};
    int in = 6;
    double dubArr[] = {1.0, 3.0, 5.0, 9.0, 11.0, 13.0};
    double db = 4.0;
    cout << "\n 'f' in chrArray: index=" << search(chrArr, ch, 6);
    cout << "\n 6 in intArray: index=" << search(intArr, in, 6);
    cout << "\n 4 in dubArray: index=" << search(dubArr, db, 6);
    system("pause");
}

Attached image(s)

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[joannesablad]

r.stiltskin, on 23 February 2012 - 10:59 AM, said:

Quote

#include"stdafx.h"
using namespace std;
template<class T>
void main()
{
// ...

You can't declare main to be a template. Your compiler should be halting at the third line and never get far enough to produce linker errors.

Get rid of that "template ..." line.

Thank you sir, Its working .. :-)

[vividexstance]

Here's a little tip, don't include the iostream in your header, you don't use it there, but put it in the main file where you actually use it. The reason for this is because whenever someone includes your header file, they will also be including any header files that are included in your header file. You want to keep your file size down, and not to include things you don't need. Since you don't use iostream in your header file, there is no reason to include it there.

[joannesablad]

vividexstance, on 23 February 2012 - 11:47 AM, said:

Here's a little tip, don't include the iostream in your header, you don't use it there, but put it in the main file where you actually use it. The reason for this is because whenever someone includes your header file, they will also be including any header files that are included in your header file. You want to keep your file size down, and not to include things you don't need. Since you don't use iostream in your header file, there is no reason to include it there.

Thanks Sir. I won't use it again.. !!