// Marty Stepp, CSE 142, Autumn 2009
// This program prints prime numbers up to a given maximum.
// The purpose of the program is to demonstrate the idea of
// fencepost problems and fencepost loops.

import java.util.*;   // for Scanner

public class PrintNumbers {
    public static void main(String[] args) {
        printPrimeNumbers(5);
        printPrimeNumbers(12);
        printPrimeNumbers(1);
        printPrimeNumbers(50);
    }
    
    // Prints all prime numbers up to the given max, separated by commas.
    // If the max is less than 2, a blank line of output is produced.
    public static void printPrimeNumbers(int max) {
        if (max >= 2) {
            System.out.print(2);
            for (int i = 3; i <= max; i++) {
                if (countFactors(i) == 2) {
                    System.out.print(", " + i);
                }
            }
        }
        System.out.println();  // to end the line
    }
    
    // Returns the number of factors of the given integer.
    // Assumes that n >= 1.
    public static int countFactors(int n) {
        int factors = 0;
        for (int i = 1; i <= n; i++) {
            // check to see whether i is a factor of n
            if (n % i == 0) {
                // i is a factor of n
                factors++;
            }
        }
        return factors;
    }
}