1-13

计算器实现

package com.lei;
import java.util.*;
public class JiSuan {
    /**
     * 属性
     */
    Scanner input = new Scanner(System.in);
    double num1;
    double num2;
    
    /**
     * 方法
     */
    
    public double suan() {
        double num3 = 0;
        System.out.print("请输入序号：1(+)2(-)3(*)4(/)：");
        int open = input.nextInt();
        switch(open) {
        case 1:
            num3 = num1+num2;
            System.out.println(num1+ "+"+num2+"="+num3);
            break;
        case 2:
            num3 = num1-num2;
            System.out.println(num1+ "-"+num2+"="+num3);
            break;
        case 3:
            num3 = num1*num2;
            System.out.println(num1+ "*"+num2+"="+num3);
            break;
        case 4:
            num3 = num1/num2;
            System.out.println(num1+ "/"+num2+"="+num3);
            break;
        default:
            System.out.println("输入错误");
            break;
        }
        return num3;
        
    }

}

package com.lei;
import java.util.*;
public class JiSuan2 {
    public static void main(String[] args) {
        JiSuan suan = new JiSuan();
        Scanner input = new Scanner(System.in);
        do {
        System.out.println("请输入第一个数：");
        suan.num1 = input.nextDouble();
        System.out.println("请输入第二个数：");
        suan.num2 = input.nextDouble();
        suan.suan();
        }while(true);

    }


}