Java 练习编写简单的计算器 -08天 学习笔记

练习

package com.xin.method;

import java.util.Scanner;

public class JiShuanQiDemo {
    
    
    /*
    写一个计算器，要求实现加减乘除，并且可以接受新的数据，通过用户交互
    思路推荐
    1.写4个方法
    2.利用循环+switch进行用户交互
    3.传递需要操作的数
    4.输出结果
     */
    public static void main ( String[] args )
    {
    
    

        Scanner scanner = new Scanner ( System.in );

        System.out.println ( "欢迎使用本工具，本工具用于计算加减乘除" );

        //选择加减乘除
        System.out.println ( "请选择加减乘除" );
        System.out.println ( "请输入数字1:加法运算" );
        System.out.println ( "请输入输入2:减法运算" );
        System.out.println ( "请输入输入3:乘法运算" );
        System.out.println ( "请输入输入4:除法运算" );
        int figure = scanner.nextInt ( );

        switch(figure){
    
    
            case 1:
                System.out.println ( "你选择的加法:\n请输入数字并回车" );
                //判断用户输入
                if(scanner.hasNextInt ( )){
    
    
                    int 	a = scanner.nextInt ( );
                    System.out.println ( "请输入下一个数字并回车" );
                    int  b = scanner.nextInt ( );
                    int B=add ( a, b );
                    System.out.println ( a + "+" + b + "=" + B );
                    System.out.println ( "计算结束，欢迎下次使用" );
                }

                break;
            case 2:
                System.out.println ( "你选择的减法: \n请输入数字并回车" );

                if(scanner.hasNextDouble ( )){
    
    
                    double c = scanner.nextDouble ( );
                    System.out.println ( "请输入下一个数字并回车" );
                    double d = scanner.nextDouble ( );
                    double D=minus ( c, d );
                    System.out.println ( c + "-" + d + "=" + D );
                    System.out.println ( "计算结束，欢迎下次使用" );

                }
                break;
            case 3:
                System.out.println ( "你选择的乘法:\n请输入数字并回车" );
                if(scanner.hasNextInt ( )){
    
    
                    int e = scanner.nextInt ( );
                    System.out.println ( "请输入下一个数字并回车" );
                    int f = scanner.nextInt ( );
                    int F =	ride ( e, f );
                    System.out.println ( e + "*" + f + "=" + F );
                    System.out.println ( "计算结束，欢迎下次使用" );
                }
                break;
            case 4:
                System.out.println ( "你选择的除法:\n请输入数字并回车" );
                if(scanner.hasNextDouble ( )){
    
    
                    double g = scanner.nextDouble ( );
                    System.out.println ( "请输入下一个数字并回车" );
                    double h = scanner.nextDouble ( );
                    double H = divide ( g, h );
                    System.out.println ( g + "/" + h + "=" + H );
                    System.out.println ( "计算结束，欢迎下次使用" );

                }
                break;
            case 6:
                System.out.println ( "输入不合法" );

        }



        scanner.close ( );
    }
    //加法运算
    public static int add ( int num1, int num2 )
    {
    
    
        return num1 + num2;
    }
    //减法运算
    public static double minus ( double num1, double num2 )
    {
    
    
        return num1 - num2;
    }
    //乘法运算
    public static int ride ( int num1, int num2 )
    {
    
    
        return num1 * num2;
    }
    //除法运算
    public static double divide ( double num1, double num2 )
    {
    
    
        return num1 / num2;

    }
}