在Java中，如何从一个方法的用户输入中获取变量，并在另一方法中使用输出? [英] In Java, how can I take a variable obtained from a user input from one method and use the output in another method?

问题描述

我不知道如何将一种方法中的变量带入另一种方法中使用，尤其是用户输入中的变量.例如，此测试程序无效.我将如何运作?

I can't figure out how to bring a variable from one method into another for use, especially that from a user input. For example, this test program doesn't work. How would I make it work?

 
import java.util.*;

public class Test {
    public static void main(String[] args) {
    input();
    output();   
   }

    public static void input() {

        Scanner console = new Scanner(System.in);

        System.out.print("This number multiplied by 7: ");
        int number = console.nextInt();

        int number7 = number * 7;
        System.out.print("The result is: " + number7);

    }
    public static void output() {

        Scanner console = new Scanner(System.in);

        System.out.print("The result multiplied by two: ");
        int number = console.nextInt();

        int number2 = number7 * 2;
        System.out.print("The result is: " + number2);
    }
}

推荐答案

(至少)有两种方法.一种是定义您的input()方法以返回output()方法所需的值:

There are (at least) two ways. One is to define your input() method to return the value needed in the output() method:

import java.util.*;

public class Test {
    public static void main(String[] args) {
    int in = input();
    output(in);   
   }

    public static int input() {

        Scanner console = new Scanner(System.in);

        System.out.print("This number multiplied by 7: ");
        int number = console.nextInt();

        int number7 = number * 7;
        System.out.print("The result is: " + number7);
        return number7;
    }

    public static void output(int number7) {

        Scanner console = new Scanner(System.in);

        System.out.print("The result multiplied by two: ");
        int number = console.nextInt();

        int number2 = number7 * 2;
        System.out.print("The result is: " + number2);
    }
}

另一种是声明一个类变量:

The other is to declare a class variable:

import java.util.*;

public class Test {
    static int number7;
    public static void main(String[] args) {
    input();
    output();   
   }

    public static void input() {

        Scanner console = new Scanner(System.in);

        System.out.print("This number multiplied by 7: ");
        int number = console.nextInt();

        int number7 = number * 7;
        System.out.print("The result is: " + number7);
    }

    public static void output() {

        Scanner console = new Scanner(System.in);

        System.out.print("The result multiplied by two: ");
        int number = console.nextInt();

        int number2 = number7 * 2;
        System.out.print("The result is: " + number2);
    }
}

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