用java生成一个计算器代码包括加减乘除乘方和根

在Java中创建一个基本的四则运算计算器，以及支持乘方和开方的功能，可以按照下面的步骤编写：

import java.util.Scanner;

public class Calculator {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.println("欢迎使用简易计算器!");

        while (true) {
            System.out.println("\n请选择操作：");
            System.out.println("1. 加法");
            System.out.println("2. 减法");
            System.out.println("3. 乘法");
            System.out.println("4. 除法");
            System.out.println("5. 幂运算");
            System.out.println("6. 开平方");
            System.out.print("7. 退出\n");

            int choice = scanner.nextInt();
            double num1, num2;

            if (choice == 7) { // 退出选项
                break;
            } else if (choice >= 1 && choice <= 4) {
                System.out.print("请输入第一个数字：");
                num1 = scanner.nextDouble();
                System.out.print("请输入第二个数字：");
                num2 = scanner.nextDouble();

                switch (choice) {
                    case 1: // 加法
                        System.out.println(num1 + " + " + num2 + " = " + add(num1, num2));
                        break;
                    case 2: // 减法
                        System.out.println(num1 + " - " + num2 + " = " + subtract(num1, num2));
                        break;
                    case 3: // 乘法
                        System.out.println(num1 + " * " + num2 + " = " + multiply(num1, num2));
                        break;
                    case 4: // 除法
                        if (num2 != 0) {
                            System.out.println(num1 + " / " + num2 + " = " + divide(num1, num2));
                        } else {
                            System.out.println("错误! 除数不能为零.");
                        }
                        break;
                }
            } else if (choice == 5) { // 幂运算
                System.out.print("请输入底数：");
                num1 = scanner.nextDouble();
                System.out.print("请输入指数：");
                num2 = scanner.nextDouble();
                System.out.println(num1 + " ^ " + num2 + " = " + power(num1, num2));
            } else if (choice == 6) { // 开平方
                System.out.print("请输入一个非负数：");
                num1 = scanner.nextDouble();
                if (num1 >= 0) {
                    System.out.println("sqrt(" + num1 + ") = " + Math.sqrt(num1));
                } else {
                    System.out.println("错误! 只能计算非负数的平方根.");
                }
            } else {
                System.out.println("无效的选择, 请重新输入.");
            }

            System.out.println();
        }
        scanner.close();
    }

    // 数学函数实现
    private static double add(double a, double b) {
        return a + b;
    }

    private static double subtract(double a, double b) {
        return a - b;
    }

    private static double multiply(double a, double b) {
        return a * b;
    }

    private static double divide(double a, double b) {
        return a / b;
    }

    private static double power(double base, double exponent) {
        return Math.pow(base, exponent);
    }
}