I would like to know how can i type in a char from a keyboard converting the char to string in an Object Oriented programming. I have a few questions down below.






And of course the errors:

1>Char to string.cpp
1>c:\documents and settings\admin\my documents\visual studio 2008\projects\char to string\char to string\char to string.cpp(24) : error C2440: '=' : cannot convert from 'char *' to 'char [20]'
1> There are no conversions to array types, although there are conversions to references or pointers to arrays
1>c:\documents and settings\admin\my documents\visual studio 2008\projects\char to string\char to string\char to string.cpp(25) : error C2664: 'strcpy' : cannot convert parameter 2 from 'char *[]' to 'const char *'
1> Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast
1>c:\documents and settings\admin\my documents\visual studio 2008\projects\char to string\char to string\char to string.cpp(31) : error C2109: subscript requires array or pointer type


Can some explain to me the meaning of cannot convert parameter 2 from 'char *[]' to 'const char *'????



Confused !!!!!!!

char* [] is an array of character pointers. Perhaps you intended to simply use char* or char[] instead? (I can't see any reason why you would need an array of pointers)

Arrays in C++ will perform automatically cast when assigned to a pointer variable, which allows pointers to mix with arrays easily.

However, being that this is C++, I'd strongly suggest you use the standard string type instead.

This post has been edited by Bench: 8 Jan, 2009 - 11:45 AM

Is there some reason you don't just use scanf?




Matthew

Look, man, I am really sorry, but I did not like your code, so I wrote one short OOP style code myself:



Try to understand this and you can always ask if you need anything else.

As for the naming, I would advise you to write class names as objects because classes represent objects. I really like Java naming convention, so I use it almost everywhere.

This post has been edited by kapax: 8 Jan, 2009 - 01:04 PM

The likely reason is that he is programming in C++, and not C. scanf is very poor style in C++, since all of its functionality is replaced by far more reliable and robust constructs from the standard stream libraries.

I'll assume you mean in general (not his specific case) - This is why:

char *GameItem[] = {
    "Broken Sword",
    "Cracked Sword",
    "Short Sword",
    "Sword",
    "Long Sword",

    "Broken Bow",
    "Cracked Bow",
    "Short Bow",
    "Bow",
    "Long Bow"
};

Now I can simply go:
printf("You have found a %s", GameItem[ItemID]);
Or countless other examples.

This post has been edited by Hyper: 9 Jan, 2009 - 11:18 PM

No, my reply was very specifically directed to the problem posed by the OP. However, even if we're talking in more general terms I would have to disagree on your rationale behind using an array of pointer-to-char in C++ (The OP was asking about C++).
Use of char[] is considered "bad" - the standard string type is far safer, more idiomatic, and more flexible. The use of arrays of any type are also generally considered "bad", since STL or boost containers are usually better for largely the same reasons. There are situations when raw arrays and pointers are unavoidable, but those circumstances are generally exceptional or can have their impact strictly limited to a small part of a program where they can't do much damage.

Here's one situation where arrays are currently unavoidable - as an initialiser for an STL container object (At least until C++0x when array initialisers will be granted more power)

const char* init[] =     "Broken Sword",
    "Cracked Sword",
    "Short Sword",
    "Sword",
    "Long Sword" };
std::vector< std::string > GameItem( init, init + sizeof(init)/sizeof(init[0]) ); 

In general, it would be hoped that init would be ignored throughout the rest of the program, on the grounds that GameItem caters for its functionality, at no additional cost, but removes any concerns about how the data is represented internally. (Though depending on exactly what GameItem is to be used for, a different STL container might be better)


There are no "never" or "always" rules in C++, and there will inevitably be some situations where char* [] is the 'best' solution to a problem (such as backward compatibility to legacy code), but as a matter of course, its best to avoid whenever possible.

If I cared that much I'd just code in Assembly all the time.
Can't get much more direct than that.

EDIT: Thanks for the thoughtful reply though. Appreciated *

This post has been edited by Hyper: 10 Jan, 2009 - 04:00 AM

Wow, thanks for the replays it was helpful

Replies *, and welcome.