You need to install the compiler, on disc 2 (or three if it comes with that) theres a gcc-<some version>mdk.i586.rpm file, this is the c compiler.
Now I've never used mandrake, but there are a few tools to install it with, I think mandy comes with urpmi, or gnorpm else theres the good old rpm tool ie: rpm -i <filename>
In order to get the full functioning of gcc, then you'll need to install the other packages it provides and is dependent on. The following comes to mind:
The gcc-g77 and gcc-chill isn't needed for C/C++ code.