java 科学计算器代码

以下是一个简单的 Java 科学计算器代码，包括基本的算术运算和三角函数：

import java.util.Scanner;
import java.lang.Math;

public class Calculator {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        System.out.println("Welcome to the Scientific Calculator!");
        System.out.println("Enter a number:");
        double num1 = input.nextDouble();
        System.out.println("Enter an operator (+, -, *, /, sin, cos, tan):");
        String operator = input.next();
        double result = 0;

        switch(operator) {
            case "+":
                System.out.println("Enter another number:");
                double num2 = input.nextDouble();
                result = num1 + num2;
                break;
            case "-":
                System.out.println("Enter another number:");
                num2 = input.nextDouble();
                result = num1 - num2;
                break;
            case "*":
                System.out.println("Enter another number:");
                num2 = input.nextDouble();
                result = num1 * num2;
                break;
            case "/":
                System.out.println("Enter another number:");
                num2 = input.nextDouble();
                result = num1 / num2;
                break;
            case "sin":
                result = Math.sin(num1);
                break;
            case "cos":
                result = Math.cos(num1);
                break;
            case "tan":
                result = Math.tan(num1);
                break;
            default:
                System.out.println("Invalid operator!");
                break;
        }

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

该代码使用了 `Scanner` 类获取用户输入，通过 `switch` 语句来判断用户选择的操作，并使用 `Math` 类中的方法来计算三角函数值。