"Why can't I use conio.h functions like clrsrc()?
Because conio.h is not part of the C standard. It is a Borland extension, and works only with Borland compilers (and perhaps some other commercial compilers). Dev-C++ uses GCC, the GNU Compiler Collection, as it's compiler. GCC is originally a UNIX compiler, and aims for portability and standards-compliance.
If really can't live without them, you can use Borland functions this way:
Include conio.h to your source, and add C:\Dev-C++\Lib\conio.o to "Further Object Files" in Project Options (where C:\Dev-C++ is where you installed Dev-C++).
Please note that conio support is far from perfect. I only wrote it very quickly." http://www14.brinkster.com/aditsu/de...faq.html#conio
[Linker error] undefined reference to `clrscr'
Why can't I use conio.h functions like clrscr, gotoxy etc?
First you should note that conio.h is a Borland extension, NOT a standard header, so Dev-C++ and MinGW are in no way required to support it. If you really want to use it, then add conio.c to your project (you can find it in the include folder), or if you have the compiled conio.o then you just need to link it. If the results are still not satisfactory, then use the native Windows console functions.
New: I provide and maintain an updated version of conio (and also winbgim) at http://www14.brinkster.com/aditsu/console/
that will probably solve some problems.
Sigo considerando que no deberias intentar usar ese codigo en Windows, con toda seguridad ese codigo fue compilado originalmente para 16 bits y no para 32 bits, pero hace como mejor te parezca.