练习：计算器

 计算器编码

package com.luckylu.method;

import java.util.Scanner;

public class Calculator {
    public static void main(String[] args) {
        Scanner s = new Scanner(System.in);
        System.out.println("请输入第一个数字：");
        double num1 = s.nextDouble();
        System.out.println("请输入预算符号：");
        String op=s.next();
        System.out.println("请输入第二个数字：");
        double num2 = s.nextDouble();

        switch (op){
            case "+" :
                double result1 = add(num1,num2);
                System.out.println(num1+" + "+num2+" = "+ result1);
                 break;
            case "-" :
                double result2 = subtract(num1,num2);
                System.out.println(num1+" - "+num2+" = "+result2);
                 break;
            case "*" :
                double result3 = multiply(num1,num2);
                System.out.println(num1+" * "+num2+" = "+result3);
                 break;
            case "/" :
                double result4 = divide(num1,num2);
                System.out.println(num1+" / "+num2+" = "+result4);
                 break;
        }
    }
    //制作计算器，Add加、subtract减、multiply乘 、divide除
    public static double add (double a,double b){
        return a+b;
    }
    public static double subtract(double a,double b){
        return a-b;
    }
    public static double multiply(double a,double b){
        return a*b;
    }
    public static double divide(double a,double b){
        return a/b;
    }
}

 输出结果

 

 

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