question2

[mohamadrezach]

why i cant use clrscr(); or sleep() or delay() or goto L and ..... in visual studio and c free and ... and what is answer

[MatthewRock]

Mohamad, I do not want to be rude, but please, use your brain. If you are asking a question, provide a meaningful title("Why are functions like clrscr() not working?" instead of "question""xlrwa""eroghiovewjo" etc.).
Second thing, use proper grammar, or at least try. You don't need to be English native speaker to write with uppercase letter in the beginning of sentence, end it with dot, and not use many colons in a row where it doesn't make sense.

As to your question - these are probably OS dependent. Where should these functions be? In what header?

[Aceix]

They are defined in the header <conio> which is not recommended by many.
Also for your title...

Aceix.

[Pter0dactyl]

@Matthew : Take it easy bud.He's new here.He'll get in shape in no time.

@Mohamad: I'm not pretty sure but clrscr() is a function used in console programming and not in windows programming.Visual Studio is a windows compiler.
Another reason may be its because of change in module of C++. Like in Dev C++ designed with C++11 module, conio.h dont even exist.

[S G H]

Conio doesn't even exist in C++03, or C++98, if this could help you.
It is a nonstandard Windows header.

[Dy7SLyTq]

Visual Studio is a windows compiler.

no. it is a windows ide. although based on some research c free is his ide, if this is indeed what he is talking about: http://www.programarts.com/cfree_en/index.htm and he (and you) meant visual c++ is the compiler. as to your question: it is not guaranteed that a compiler supply it. if i remember my teachings correctly, it is not supported by mingw, and is outclassed by <windows.h>