You should have project builder, i think it's called in Jaguar. It's Apples IDE. Look for a folder in Applications->Installers->Developers Tools
Here you should find an installer for it.
Another way is open a terminal. go to Applications->Utilities
here you'll find the terminal.
once you have you code written, i.e. you *.c or *.cc or *.cpp files
use gcc or g++ filename.
gcc is for C
g++ is for C++
but, I also think you can use either for both C and C++. What I mentioned befoer is the recommendations.