计算器，用java通过命令行传参实现

一.代码

package com.zhuo.base;

public class Calculator {
    
    
    public static void main(String[] args) {
    
    
        /*检查字符串数*/
        if (args.length != 3){
    
    
            System.out.println("Usage: java calculator operand1 and operand2");
            System.exit(0);
        }
        int result = 0;//操作的结果
        /*确定操作符*/
        switch (args[1].charAt(0)) {
    
    
            case '+': result = Integer.parseInt(args[0]) + Integer.parseInt(args[2]);break;
            case '-': result = Integer.parseInt(args[0]) - Integer.parseInt(args[2]);break;
            case '.': result = Integer.parseInt(args[0]) * Integer.parseInt(args[2]);break;
            case '/': result = Integer.parseInt(args[0]) / Integer.parseInt(args[2]);break;
        }
        System.out.println(args[0] + args[1] + args[2] + "=" + result);
    }
}

二.实现

1. 打开命令行
   
   

2. Dos命令

D:\IdeaProjects\JavaSE\Practise\src\com\zhuo\base>javac Calculator.java

D:\IdeaProjects\JavaSE\Practise\src\com\zhuo\base>cd ..

D:\IdeaProjects\JavaSE\Practise\src\com\zhuo>cd ..

D:\IdeaProjects\JavaSE\Practise\src\com>cd ..
D:\IdeaProjects\JavaSE\Practise\src>java com.zhuo.base.Calculator 45 + 56
45+56=101

D:\IdeaProjects\JavaSE\Practise\src>java com.zhuo.base.Calculator 45 - 56
45-56=-11

D:\IdeaProjects\JavaSE\Practise\src>java com.zhuo.base.Calculator 45 . 56
45.56=2520

D:\IdeaProjects\JavaSE\Practise\src>java com.zhuo.base.Calculator 45 / 56
45/56=0