/*
   I figured I'd describe the code here, since I didn't write it.
   Since I failed the lesson, I'll at least explain it. To continue on
   then!
*/

#include <stdio.h>
//#include <stdlib.h> is not needed, don't know why you put it there.

#define FIRST 2 // Obvious
#define LAST 1000 // Read previous comment.

char prime[1001] = {0}; /* Dont' understand "{0}", errors without it.
                           Either way, declare array "prime" with 1001
			   elements, with the last element declared NULL
			*/
main(void)
{
	unsigned long d=0; // I know unsigned means 16 or 32 bits,
	unsigned long x=0; // and long means 32..But why use it? 

	printf("Beginning\!\n");
	for (x = FIRST; x <= LAST; x++) // Obvious
	{
		for (d=2; d<x; d++) // Read above comment
		{	
			// if x%d = 0, prime[x] = 1
			// kinda stoned, may have mixed up 0/1
			if (!(x % d)) prime[x] = 1;
		}
	}

	for (x = FIRST; x <= LAST; x++)
	{
		// if prime[x] = 0 print element x
		if (!prime[x]) printf("%i\n",x);
	}
	return 0;
}