用java写一个简易的计算器包括科学计算器

好的，下面是Java代码实现简易计算器和科学计算器的功能。

简易计算器：

import java.util.Scanner;

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

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

        System.out.print("请输入运算符（+、-、*、/）：");
        operator = sc.next().charAt(0);

        System.out.print("请输入第二个数字：");
        num2 = sc.nextDouble();

        switch (operator) {
            case '+':
                result = num1 + num2;
                break;
            case '-':
                result = num1 - num2;
                break;
            case '*':
                result = num1 * num2;
                break;
            case '/':
                result = num1 / num2;
                break;
            default:
                System.out.println("错误的运算符");
                return;
        }

        System.out.println("结果：" + result);
    }
}

科学计算器：

import java.util.Scanner;

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

        System.out.println("请选择计算模式：");
        System.out.println("1.普通计算器");
        System.out.println("2.科学计算器");
        choice = sc.nextInt();

        if (choice == 1) {
            System.out.print("请输入第一个数字：");
            num1 = sc.nextDouble();

            System.out.print("请输入运算符（+、-、*、/）：");
            operator = sc.next().charAt(0);

            System.out.print("请输入第二个数字：");
            num2 = sc.nextDouble();

            switch (operator) {
                case '+':
                    result = num1 + num2;
                    break;
                case '-':
                    result = num1 - num2;
                    break;
                case '*':
                    result = num1 * num2;
                    break;
                case '/':
                    result = num1 / num2;
                    break;
                default:
                    System.out.println("错误的运算符");
                    return;
            }

            System.out.println("结果：" + result);
        } else if (choice == 2) {
            System.out.print("请输入数字：");
            num1 = sc.nextDouble();

            System.out.println("请选择函数：");
            System.out.println("1.平方根");
            System.out.println("2.正弦函数");
            System.out.println("3.余弦函数");
            System.out.println("4.正切函数");
            int function = sc.nextInt();

            switch (function) {
                case 1:
                    result = Math.sqrt(num1);
                    break;
                case 2:
                    result = Math.sin(num1);
                    break;
                case 3:
                    result = Math.cos(num1);
                    break;
                case 4:
                    result = Math.tan(num1);
                    break;
                default:
                    System.out.println("错误的函数");
                    return;
            }

            System.out.println("结果：" + result);
        } else {
            System.out.println("错误的选择");
        }
    }
}

希望能够帮到你！