A. You need GNU project C and C++ compiler for compiling C program and creating an executable file. Most Unix and Linux (*BSD) start their C compiler by the name cc. But you can use gcc command to compile program. First make sure you have gcc installed:

Type the following command to verify that gcc is installed:

$ which gcc
Output:

/usr/bin/gcc

Find out version of gcc:
$ gcc --version
Output:

gcc (GCC) 4.0.3 20060212 (prerelease) (Debian 4.0.2-9)
Copyright (C) 2006 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

To compile C program you need to use syntax as follows:
gcc program.c -o program-output

Consider following C program:
$ vi first.c
Type the following lines (program):

#include <stdio.h>
int main(void){
printf("My first C program\n");
return 0;
}

Compile C program first.c and create an executable file called first:
$ gcc first.c -o first
OR
$ cc first.c -o first

Execute program first:
$ ./first
Output:

My first C program

However, both FreeBSD and Linux support direct make (GNU make utility to maintain groups of programs) command on C program without writing a make file.
Remove first program using rm command:
$ rm first
$ make first

Output:

cc   first.o   -o first

Execute program first:
$ ./first
Please note that above hack works with GNU make only.