contrib/top/prime.c

   1 /*
   2  * Prime number generator.  It prints on stdout the next prime number
   3  * higher than the number specified as argv[1].
   4  */
   5
   6 #include <stdio.h>
   7 #include <math.h>
   8
   9 main(argc, argv)
  10
  11 int argc;
  12 char *argv[];
  13
  14 {
  15     double i, j;
  16     int f;
  17
  18     if (argc < 2)
  19     {
  20         exit(1);
  21     }
  22
  23     i = atoi(argv[1]);
  24     while (i++)
  25     {
  26         f=1;
  27         for (j=2; j<i; j++)
  28         {
  29             if ((i/j)==floor(i/j))
  30             {
  31                 f=0;
  32                 break;
  33             }
  34         }
  35         if (f)
  36         {
  37             printf("%.0f\n", i);
  38             exit(0);
  39         }
  40     }
  41 }