C program that finds the nth prime.
#include <stdlib.h>
#include <inttypes.h>
#include <stdio.h>
int main(int argc, char** argv)
{
uint64_t n = 1000;
if (argc > 1 && argv[1])
n = atol(argv[1]);
printf("%" PRIu64 "th prime = %" PRIu64 "\n", n, prime);
return 0;
}