/* Primes finder (primes.c) by Cobi *//* * We need this library (printf?). */#include <stdio.h>/* * We need this library for atoi(). */#include <stdlib.h>int main (int argc, char **argv) { /* Our main program. */ /* Make sure we have the correct arguementes. */ if (argc < 2) { /* We don't, complain. */ printf ("This binary requires the start"); printf ("and stop values as arguements 1 "); printf ("and 2.\nExample: %s <start> <st",argv[0]); printf ("op>\n"); return 0; } /* We initialize our outer loop variables. */ unsigned long bigcounter = atoi(argv[1]); unsigned long upperbound = atoi(argv[2]); /* Then we initialize our inner loop variables. */ unsigned long to = 0; unsigned long counter = 0; unsigned long halfto = 0; /* * And then we initialize our variable to * hold the status of the current check. */ unsigned short found = 0; /* * We make a big loop through each integer * between argv[1] and argv[2]. */ while (bigcounter <= upperbound) { /* Reset any variables for the inner loop. */ counter = 2; to = bigcounter; found = 0; halfto = to / 2; /* * We make an inner loop to loop through * each integer between 2 and half of the * integer we are checking for primality. */ while (counter < halfto) { /* * We check to see if the counter devides * evenly into the integer we are checking * for primality. */ if (to % counter == 0) { /* It is not prime, set found = 1 */ found = 1; /* and set counter so the loop exits. */ counter = to; } /* Increment the counter. */ counter++; } /* * Check to see if the loop exited normally * as opposed to prematurely. */ if (found == 0) { /* * If it exited normally, we found * ourselves a prime! Print it out * so the owner can see. */ printf("%d\n",to); } /* Increment the counter. */ bigcounter++; } /* Exit successfully. */ return 0;}