-:    0:Source:p1.c
        -:    0:Graph:p1.gcno
        -:    0:Data:p1.gcda
        -:    0:Runs:1
        -:    0:Programs:1
        -:    1:#include <stdio.h>
        -:    2:#include <math.h>
        -:    3:
        -:    4://This program uses two functions to compute all primes up to n
        -:    5://// Then checks that the two functions agree, printing an error if not
        -:    6://// Compile use the -lm flag to get the sqrt from math library
        -:    7://
        -:    8://
    19998:    9:  int prime1(n) // a slow prime test
        -:   10:                int n;
        -:   11:                { int i;
 11552904:   12:                  for (i=2; i < n; i++)
 11550446:   13:                        if (n%i == 0)
    17540:   14:                          return 0;
     2458:   15:                  return 1;
        -:   16:                }
        -:   17:
   118756:   18:int root(n) // computes integer sqrt of n
        -:   19:int n;
   118756:   20:{return (int) sqrt( (double) n) ; }
        -:   21:
     9999:   22:int prime2(n) // a faster prime test only test up to sqrt(n)
        -:   23:int n;
        -:   24:
        -:   25:{ int i;
   118756:   26:  for (i=2; i <= root(n) ; i++)
   117527:   27:        if (n%i == 0)
     8770:   28:          return 0;
     1229:   29:  return 1;
        -:   30:}
        -:   31:
        1:   32:		 main() {
        -:   33:
        -:   34:                int i, n, pcount;
        -:   35:
        1:   36:                n = 10000;
        1:   37:                pcount=0;
        -:   38:
    10000:   39:                for (i=2; i <= n; i++)
     9999:   40:                {if( prime1(i) != prime2(i) )
    #####:   41:                    printf("error, wrong answer for %d\n",i);
     9999:   42:                if(prime1(i) ) pcount++;
        -:   43:                }
        -:   44:
        1:   45:                printf("primes found less than %d = %d\n",n,pcount);
        -:   46:
        1:   47:                }
        -:   48: