java实现计算器代码怎么写

以下是一个简单的Java计算器代码示例：

import java.util.Scanner;public class Calculator {    public static void main(String[] args) {        Scanner scanner = new Scanner(System.in);                System.out.println("Enter the first number: ");        double num1 = scanner.nextDouble();                System.out.println("Enter the second number: ");        double num2 = scanner.nextDouble();                System.out.println("Enter the operation (+, -, *, /): ");        char operation = scanner.next().charAt(0);                double result = 0;                switch(operation) {            case '+':                result = num1 + num2;                break;            case '-':                result = num1 - num2;                break;            case '*':                result = num1 * num2;                break;            case '/':                result = num1 / num2;                break;            default:                System.out.println("Invalid operation.");        }                System.out.println("Result: " + result);                scanner.close();    }}

此代码通过用户输入两个数和运算符，然后根据运算符执行相应的运算，最终输出结果。您可以根据自己的需求对此代码进行修改和扩展。