Mega Code Archive
Test for primes
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#include <stdio.h>
#include <getopt.h>
#include <stdlib.h>
int isprime(int value);
int main(int argc, char *argv[]) {
int number = 0;
if(argc != 2) {
fprintf(stderr, "Usage: isprime INT\n");
return 1;
} else
number = atoi(argv[1]);
if(isprime(number) == 0)
printf("%2d is NO prime\n", number);
else
printf("%2d is a prime...\n", number);
return 0;
}
int isprime(int value) {
int retval = -1;
int i = 0;
for(i = 2; i <= value / 2; i++) {
if(value % i == 0) {
retval = 0;
break;
}
}
return retval;
}
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