java25、题目：将一个正整数分解质因数。例如：输入90打印出90=2335。程序分析：对n进行分解质因数应先找到一个最小的质数k然后按下述步骤完成：

import java.util.Scanner;

public class PrimeFactorization {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.print("请输入一个正整数：");
        int num = scanner.nextInt();
        System.out.print(num + "=");
        primeFactorization(num);
    }

    public static void primeFactorization(int num) {
        for (int i = 2; i <= num; i++) {
            while (num % i == 0) {
                System.out.print(i);
                num /= i;
                if (num != 1) {
                    System.out.print("*");
                }
            }
        }
    }
}

运行结果： 请输入一个正整数：90 90=233*5