用java编写简单计算器

好的，以下是一个简单的 Java 计算器程序，可以进行加、减、乘、除四则运算：

import java.util.Scanner;

public class Calculator {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        double num1, num2, result;
        char operator;

        System.out.print("请输入第一个数字：");
        num1 = scanner.nextDouble();
        System.out.print("请输入运算符（+、-、*、/）：");
        operator = scanner.next().charAt(0);
        System.out.print("请输入第二个数字：");
        num2 = scanner.nextDouble();

        switch (operator) {
            case '+':
                result = num1 + num2;
                System.out.println(num1 + " + " + num2 + " = " + result);
                break;
            case '-':
                result = num1 - num2;
                System.out.println(num1 + " - " + num2 + " = " + result);
                break;
            case '*':
                result = num1 * num2;
                System.out.println(num1 + " * " + num2 + " = " + result);
                break;
            case '/':
                if (num2 == 0) {
                    System.out.println("除数不能为零");
                    break;
                }
                result = num1 / num2;
                System.out.println(num1 + " / " + num2 + " = " + result);
                break;
            default:
                System.out.println("错误的运算符");
        }

        scanner.close();
    }
}

你可以将以上代码保存为 Calculator.java 文件，然后在命令行中使用以下命令编译和运行程序：

javac Calculator.java
java Calculator

然后按照程序提示输入两个数字和运算符即可。