用Java实现两个数的加减乘除简易计算器

用Java实现两个数的加减乘除简易计算器

写在前面：仅用于帮助新手理解，还有很大的优化空间，欢迎大家提出不同的意见或者建议~

笔者也是新手，代码可能存在过于冗杂或者有一些没有考虑到的方面等这些问题，望海涵。

package com.chen.method;

import java.util.Scanner;

public class Demo08 {
    public static void main(String[] args) {
        System.out.println("请选择您要进行的运算a代表+，b代表-，c代表*，d代表/:");
        Scanner scanner = new Scanner(System.in);
        String sc = scanner.next();
        char change = sc.charAt(0);
        switch (change){
            case 'a':
                System.out.println("请输入您要计算的数据并用空格隔开：");
                Scanner scanner1 = new Scanner(System.in);
                int sum1 = scanner1.nextInt();
                int sum2 = scanner1.nextInt();
                int nember = add(sum1,sum2);
                scanner1.close();
                System.out.println("这两个数的和是："+nember);
                break;
            case 'b':
                System.out.println("请输入您要计算的数据并用空格隔开：");
                Scanner scanner2 = new Scanner(System.in);
                int sum11 = scanner2.nextInt();
                int sum22 = scanner2.nextInt();
                int nember1 = sub(sum11,sum22);
                scanner2.close();
                System.out.println("这两个数的差是："+nember1);
                break;
            case 'c':
                System.out.println("请输入您要计算的数据并用空格隔开：");
                Scanner scanner3 = new Scanner(System.in);
                int sum31 = scanner3.nextInt();
                int sum32 = scanner3.nextInt();
                int nember2 = mul(sum31,sum32);
                scanner3.close();
                System.out.println("这两个数的积是："+nember2);
                break;
            case 'd':
                System.out.println("请输入您要计算的数据并用空格隔开：");
                Scanner scanner4 = new Scanner(System.in);
                double sum41 = scanner4.nextInt();
                double sum42 = scanner4.nextInt();
                double nember3 = div(sum41,sum42);
                scanner4.close();
                System.out.println("这两个数的商是："+nember3);
                break;
        }
    }
    public static int add(int a,int b){
        return a+b;
    }
    public static int sub(int a,int b){
        return a-b;
    }
    public static int mul(int a,int b){
        return a*b;
    }
    public static double div(double a,double b){
        return a/b;
    }
}