Java 分解失败 - 为什么会循环？

Question

我正在尝试获取代码来查找用户输入的因子，给出用户输入的素因式分解，并给出 lcm 和 gcm。这应该很简单。这是一门编程入门类(class)，但对我来说进展太快了。我花了几个小时阅读和研究并试图让这段代码发挥作用。请帮忙。

import java.util.Scanner;


public class PattersonFactorization {


    public static void main(String[] args) 
    {
        //create scanner to obtain input from command window
        Scanner input = new Scanner(System.in);

        //initialization phase
        int input1 = 0; //initialize first input from user
        int input2 = 0; //initialize second input from user


        //prompt twice for two inputs from user 
        //until they enter a positive value for each input

        do
        {
            System.out.println("Please provide your first positive number: ");
            input1 = input.nextInt();
        }//end do for input1
        while(input1 <= 0);

        do
        {
            System.out.println("Please provide your next positive number: ");
            input2 = input.nextInt();
        }//end do for input2
        while(input2 <= 0);

        // call methods for factorization calculations
        calculateFactors(input1);
        calculateFactors(input2);
        calculatePrime(input1);
        calculatePrime(input2);
        calculateLCM(input1, input2);
        calculateGCF(input1, input2);


    }//end of main

    public static void calculateFactors(int input)
    {

        for(int countFactor = 1; countFactor < input; countFactor++)
        {
            if(countFactor % input == 0); 
            System.out.println(countFactor);
        }

    }//end of calculateFactors

    public static void calculatePrime(int input)
    {
        for(int countPrime = 1; countPrime < input; countPrime++)
        {
            if(countPrime % input == 0);
            System.out.println(countPrime);
            input = input/countPrime;
            countPrime--;
        }
    }//end of calculatePrime

    public static void calculateLCM(int input1, int input2)
    {
        for(int factorNum = 1; input1 % factorNum != 0 && input2 % factorNum != 0; factorNum++)
        System.out.println(factorNum);
    }//end of calculateLCM

    public static void calculateGCF(int input1, int input2)
    {
        for(int factorNum = input1; input1 % factorNum != 0 && input2 % factorNum != 0; factorNum--)
        System.out.println(factorNum);
    }

}//end of class

`

Answer 1

我相信问题出在这里:

        for(int countPrime = 1; countPrime < input; countPrime++)
        {
            if(countPrime % input == 0);
            System.out.println(countPrime);
            input = input/countPrime;
            countPrime--;
        }

您在递增循环中递减 countPrime。因此它的值永远不会改变。