The following program shows how to achieve this:
main( int argc, char *argv[ ], char *env[ ] )
int i = 0 ;
clrscr( ) ;
while ( env[ i ] )
printf ( "\n%s", env[ i++ ] ) ;
main( ) has the third command line argument env, which is an array of pointers to the strings. Each pointer points to an environment variable from the list of environment variables.