Java循环实现计算器连续加减乘除

在Java中，我们可以使用while或do-while循环来实现一个简单的计算器，让用户可以连续输入加、减、乘、除操作。下面是一个基本的例子：

import java.util.Scanner;

public class Calculator {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        double num1 = 0, result = 0;
        char operator;

        System.out.println("请输入第一个数字：");
        num1 = scanner.nextDouble();

        while (true) {
            System.out.println("\n请选择操作 (+, -, *, /): ");
            operator = scanner.next().charAt(0);

            switch (operator) {
                case '+':
                    System.out.println("请输入第二个数：");
                    double num2 = scanner.nextDouble();
                    result = num1 + num2;
                    System.out.println("结果是：" + result);
                    num1 = result; // 更新num1以便下一次运算
                    break;
                case '-':
                    System.out.println("请输入第二个数：");
                    num2 = scanner.nextDouble();
                    result = num1 - num2;
                    System.out.println("结果是：" + result);
                    num1 = result;
                    break;
                case '*':
                    System.out.println("请输入第二个数：");
                    num2 = scanner.nextDouble();
                    result = num1 * num2;
                    System.out.println("结果是：" + result);
                    num1 = result;
                    break;
                case '/':
                    if (num2 != 0) { // 防止除数为零
                        System.out.println("请输入第二个数：");
                        num2 = scanner.nextDouble();
                        result = num1 / num2;
                        System.out.println("结果是：" + result);
                        num1 = result;
                    } else {
                        System.out.println("错误！除数不能为零。");
                    }
                    break;
                default:
                    System.out.println("无效的操作符，请重新选择。");
            }

            System.out.print("是否继续计算？(y/n)");
            String continueChoice = scanner.next().toLowerCase();
            if (!continueChoice.equals("y")) {
                break; // 用户选择退出，则跳出循环
            }
        }

        scanner.close();
    }
}