java多类程序

Question

您好，我试图创建一个计算器，可以进行加法、减法、乘法和除法运算来挑战我自己，但我发现自己被困在开关部分：（我将指出开关消息中的错误，即“类型加法等中的方法加法等（字符串[]）不适用于参数（）我相信问题在于其他阶级的公共空虚

脚本：

public class ComputronCalc {
    public static void main(String args[]) {

        int mode;
        mode = 1;

        Addition ADD = new Addition();
        Subtraction SUB = new Subtraction();
        Multiplication MUL = new Multiplication();
        Division DIV = new Division();

        System.out.println("Hello welcome to the Computron fully functional calculator, coded by Samuel Cole, designed by Dwight Schrute.");

        switch(mode) {
        case 1:
            ADD.Addition();<-----------addition is underlined in red
            break;
        case 2:
            SUB.Subtraction();<-------------same
            break;
        case 3:
            MUL.Multiplication();<---------------same
            break;
        case 4:
            DIV.Division();<----------------same
            break;
        default:
            System.out.println("You have not selected a mode, do so by editing the mode variable in the source.");
        }
    System.out.println("Thank you for choosing Computron.");
    }
}

import java.util.Scanner;

public class Addition {
    public void Addition(String Args[]) {
        Scanner input = new Scanner(System.in);

        double fnum, snum, answer;
        System.out.println("Type the first number you desire to calculate.");
        fnum = input.nextDouble();
        System.out.println("Type the second number you desire to calculate.");
        snum = input.nextDouble();
        System.out.println("Calculating...");
        answer = fnum + snum;
        System.out.println(answer);

    }
}

import java.util.Scanner;

public class Multiplication {
    public void Multiplication(String Args[]) {
        Scanner input = new Scanner(System.in);

        double fnum, snum, answer;
        System.out.println("Type the first number you desire to calculate.");
        fnum = input.nextDouble();
        System.out.println("Type the second number you desire to calculate.");
        snum = input.nextDouble();
        System.out.println("Calculating...");
        answer = fnum * snum;
        System.out.println(answer);

    }
}

import java.util.Scanner;

public class Division {
    public void Division(String Args[]) {
        Scanner input = new Scanner(System.in);

        double fnum, snum, answer;
        System.out.println("Type the first number you desire to calculate.");
        fnum = input.nextDouble();
        System.out.println("Type the second number you desire to calculate.");
        snum = input.nextDouble();
        System.out.println("Calculating...");
        answer = fnum / snum;
        System.out.println(answer);

    }
}

注意：我使用的是eclipse，所以每个类都位于不同的页面上

Answer 1

虽然尖锐的问题是，您需要更改方法签名以不包含任何参数，或者更改方法调用以发送参数，但我认为有一个更好的解决方案，您应该使用concider

将操作类中的方法更改为构造函数：

public class Addition { 
    public Addition() {
    //...
    }
}

然后，无需为每次运行实例化所有操作，开关将变为：

switch(mode) {
case 1:
    Addition();
    break;
case 2:
    Subtraction();
    break;
case 3:
    Multiplication();
    break;
case 4:
    Division();
    break;
default:
    System.out.println("You have not selected a mode, do so by editing the mode variable in the source.");
}

Answer 2

您的方法需要参数“args”，而您不使用它。把它拿走。例如：

public void Addition(String Args[]) {

变成：

public void Addition() {

（顺便说一句，您的代码不遵循Oracle Java Naming Convention）

Answer 3

四个运算符类中没有函数的任何参数（在本程序中为String[]args参数）。你的程序应该在没有它们的情况下运行

public class Addition { 
    public Addition() {
    //...
    }
}

其他课程也是如此

public class Subtraction { 
    public Subtraction() {
    //...
    }
}

public class Multiplication{ 
    public Multiplication() {
    //...
    }
}

public class Division { 
    public Division() {
    //...
    }
}