变量不会递增。-java中的最大公约数

Question

我的任务是接受两个分数并求和，然后以最简单的形式返回。

出于某种原因，“gcd=i执行时不运行，因此我的程序在运行时进入无限循环。

import java.util.*;

class fraction {
    public static void main(String[] args) {
        int num1, den1, num2, den2;
        Scanner sc = new Scanner(System.in);
        /* System.out.print("Enter first numerator:");
        num1 = sc.nextInt();
        System.out.print("Enter first denominator:");
        den1 = sc.nextInt();
        System.out.print("Enter second numerator:");
        num2 = sc.nextInt();
        System.out.print("Enter second denominator:");
        den2 = sc.nextInt(); */

        num1 = 1;
        den1 = 2;
        num2 = 1;
        den2 = 2;
        System.out.print(num1 + "/" + den1 + " + " + num2 + "/" + den2 + " is equal to ");

        int num = num1 * den2 + den1 * num2;
        int dum = den1 + den2;
        System.out.println(num + "/" + dum);
        System.out.println(num % dum);

        int gcd = 2;
        while (num % dum == 0) {
            for (int i = 1; i < num && i < dum; ++i) {
                if (num % i == 0 && dum % i == 0) {
                    gcd = i;//This line.
                    System.out.println(gcd + " " + i);
                }
            }
                
            num = num / gcd;
            dum = dum / gcd;
        }

        System.out.println(num + "/" + dum);
    }
}

Answer 1

你总是输入gcd=i；

问题是，在陈述的最后，你有

num1    1
den1    2
num2    1
den2    2
num     2
dum     2
gcd     1

因此num=num/gcd返回2，并且dum=dum/gcd=2。所以你不能走出while循环

也许你可以在for循环中解决（i=2...）