input value from terminal to c
#include <stdio.h>
#include <stdlib.h>
int main(int argc, char *argv[])
{
   int rings;
   if(argc != 2) {
       printf("Usage: %s number-of-rings\n",argv[0]);
       return 1;
   }
   rings = atoi(argv[1]);
   printf("Using number-of-rings = %d\n", rings);
...
   return 0;
}
