Question

我在编程类中完成这个因子生成器时遇到了一些麻烦。它应该采用一个数字，并使用nextFactor方法打印出所有因子。当我将数字设置为因子而不是150时，它打印出“1 2 3 5”，它应该打印“2 3 5 5”。那么，我应该从哪里开始呢？我看过Java - Factor Generator program nextfactor method，但它没有发现我的任何查询

public class FactorGenerator
{
    //user inputs int from scanner in FactorTester class
    public FactorGenerator(int i)
    {
        num = i;
    }

    //Checks to see if num can be factored, but does not factor it.
    //Goes through all possible factors of num and returns true if the remainder == 0
    public boolean hasMoreFactors()
    {       
        for(int i = 1; i < num; i++)
        {
            //check if the remainder is anything other then 0
            if(num % i == 0)
            {
                return true;
            }
        }

        return false;
    }

  //Actually factors num and prints out the factor at the end of every loop.
    public void nextFactor() 
    {
        for(int i = 1; i < num; i++)
        {
            //check if the remainder is anything other then 0
            if(num % i == 0)
            {
                System.out.println(i);
                num /= i;
            }            


        }

        System.out.println("Done.");
    }

    private int num;
}

Answer 1

尝试这些因素可以重复，因此您需要循环，直到您提取了该因子的所有实例

public void nextFactor() 
{
    for(int i = 2; i <= num; i++)
    {
        //check if the remainder is anything other then 0
        while (num >= i && num % i == 0)
        {
            System.out.println(i);
            num /= i;
        }           

    }

    System.out.println("Done.");
}

另一种方法是在循环体中进行增量

public void nextFactor() 
{
    for(int i = 2; i <= num;)
    {
        //check if the remainder is anything other then 0
        if (num % i == 0)
        {
            System.out.println(i);
            num /= i;
        } else {
           i++;
        }

    }

    System.out.println("Done.");
}

Answer 2

首先，它将始终打印出1，因为任何整数/ 1将始终具有零余数。如果你想跳过1，你可以从你的2开始，而不是1。

我建议这样的事情:(注意这部分基于BevynQ的答案）：

for(int i = 2; i <= num; i++){
    while (num >= i && num % i == 0) {
        System.out.println(i);
        num /= i;
    }
}

因子生成器的麻烦

2 个答案: