#include <stdio.h>
#include <stdlib.h>

#define TRUE 0
#define FALSE 1

/* next_prime#.c */

int find_next_prime(int);

void main(void)
{
	int number = -1, next_prime;

	while (number <= 0) {
		printf("Enter a positive number: ");
		scanf("%d", &number);
	}

	next_prime = find_next_prime(number);
	if (number == next_prime)
		printf("%d is prime!\n", number);
	else
		printf("The next prime number after %d is %d.\n", number, next_prime);

	exit(1);
}

int find_next_prime(int number)
{
	int i, j, prime = FALSE;

	if (number == 1 || number == 2) {
		return number;
	}

	while (prime != TRUE && number > 2) {
  		for (j = number++; j != 99999999; j++) {
   			for (i = 2; i < number; i++) {
    			prime = TRUE;
    			if (j % i == 0) {
    				prime = FALSE;
    				break;
    			}
    		}
    		if (prime == TRUE)
    			break;
    	}
    }
    
    return j;
}