/* PrimeNumberTools.java */ public class PrimeNumberTools { public void printPrimeFactors(int num) { int whichprime = 1; int prime; String prefix; prefix = "primeFactors("+num+")= "; while (num > 1) { prime = getPrime(whichprime); if (num % prime == 0) { System.out.print(prefix+prime); prefix = " "; num /= prime; } else { ++whichprime; } } System.out.println(); } public int getPrime(int cnt) { int i = 1; int ret = 2; while (i < cnt) { ++ret; if (isPrime(ret)) { ++i; } } return ret; } private boolean isPrime(int num) { for (int i = 2; i < num; ++i) { if (num % i == 0) { return false; } } return true; } }