Question

我正在做一个简单的分数测试课。我希望我的程序能够做到这一点。

如果用户输入0＆gt;循环重复，直到用户输入不是0的数字

在我的课堂上，它没有这样做。我尝试将其与do while条件与if语句混合，并初始化语句true或false。我卡住了所以请我帮忙。

这里我的分数类：

import java.util.*;


public class FractionTest {
    public static void main(String args[]) {
        Scanner input = new Scanner(System.in);

        boolean valid = true;
        int num, den;

        den = 0;

        do {
            System.out.println("Please enter the numerator: ");
            num = input.nextInt();
            System.out.println("Please enter the denominator: ");
            den = input.nextInt();
            if (den == 0 && valid) {
                System.out.println("denominator cannot be zero");
                System.out.println("Please enter the numerator: ");
                num = input.nextInt();
                System.out.println("Please enter the denominator: ");
                den = input.nextInt();
            }

        } while (den != 0 && !valid);
        System.out.println("Decimal is " + result(num, den));
    }

    public static double result(int x, int y) {
        return (x / y);

    }
}

Here the program once I run the Test

Answer 1

问题并不完全清楚，但我认为你要求每当分母变为零时继续循环，否则计算答案和返回值。我根据

对您的代码进行了一些更改

public class FractionTest {
public static void main(String args[]) {
    Scanner input = new Scanner(System.in);

    boolean valid = true;
    int num, den;

    den = 0;

    while(den == 0) {
        System.out.println("Please enter the numerator: ");
        num = input.nextInt();
        System.out.println("Please enter the denominator: ");
        den = input.nextInt();
        if (den == 0 && valid) {
            System.out.println("denominator cannot be zero");
            System.out.println("Please enter the numerator: ");
            num = input.nextInt();
            System.out.println("Please enter the denominator: ");
            den = input.nextInt();
        }

    }
    System.out.println("Decimal is " + result(num, den));
    return;
}

public static double result(int x, int y) {
    return ((1.0)*x / y);

}

}

Answer 2

将main方法中的代码更改为：

    Scanner input = new Scanner(System.in);
    int num, den;

    do {
        System.out.println("Please enter the numerator: ");
        num = input.nextInt();
        System.out.println("Please enter the denominator: ");
        den = input.nextInt();
        if (den!=0)
            System.out.println("Decimal is " + result(num, den));
        else
            System.out.println("Denominator shouldnt be 0");
    } while (den == 0);
    input.close();

没有必要初始化＆＃39; den＆＃39;因为价值无论如何被取代。
不需要拥有＆＃39;布尔变量＆＃39;因为它的价值永远不会改变
如果den == 0，则无需像循环那样在循环内重新请求输入无论如何重新运行

Answer 3

我只想分开您的输入验证：

        System.out.println("Please enter the numerator: ");
        num = input.nextInt();
    do{
        System.out.println("Please enter the denominator: ");
        System.out.println("denominator cannot be zero");
        den = input.nextInt();
    } while (den == 0);
    System.out.println("Decimal is " + result(num, den));

如果你需要对你的分子进行输入验证，那就做一下。您的有效布尔值也始终为true。永远不要修改为假。如果x为真，则逻辑（x ^ True）将始终为。

重复循环，直到输入对小数类有效

3 个答案: