// command-line arguments
//
#include <stdio.h>

int main( int argc, char *argv[]) // argument count and vector (array of strings)
{
 // view:
  for( int i = 0; i < argc; ++i) printf( "%i: %s\n", i, argv[i]);

 // process:
 int p = 0; if( argc > 1) if( argv[1][0] == 'p') p = 1;
 printf( "p = %i\n", p);
}

/* sample runs:

$ ./a.out a bb cc
0: ./a.out
1: a
2: bb
3: cc
p = 0

$ ./a.out p
0: ./a.out
1: p
p = 1

*/