Week 1 综合项目：命令行计算器

cd /Users/yao/Projects
dotnet new console -n Calculator
cd Calculator
code .

using System;
using System.Collections.Generic;
 
class Calculator
{
    static List<string> history = new List<string>();
 
    static void Main()
    {
        while (true)
        {
            Console.WriteLine("\n=== 计算器 ===");
            Console.WriteLine("1. 加法");
            Console.WriteLine("2. 减法");
            Console.WriteLine("3. 乘法");
            Console.WriteLine("4. 除法");
            Console.WriteLine("5. 查看历史");
            Console.WriteLine("6. 清除历史");
            Console.WriteLine("7. 退出");
            Console.Write("请选择: ");
 
            string? choice = Console.ReadLine();
 
            if (choice == "7") break;
 
            switch (choice)
            {
                case "1":
                    Calculate("+");
                    break;
                case "2":
                    Calculate("-");
                    break;
                case "3":
                    Calculate("*");
                    break;
                case "4":
                    Calculate("/");
                    break;
                case "5":
                    ShowHistory();
                    break;
                case "6":
                    ClearHistory();
                    break;
                default:
                    Console.WriteLine("无效选择");
                    break;
            }
        }
    }
 
    static void Calculate(string op)
    {
        Console.Write("输入第一个数: ");
        if (!double.TryParse(Console.ReadLine(), out double a))
        {
            Console.WriteLine("输入无效");
            return;
        }
 
        Console.Write("输入第二个数: ");
        if (!double.TryParse(Console.ReadLine(), out double b))
        {
            Console.WriteLine("输入无效");
            return;
        }
 
        double result = op switch
        {
            "+" => a + b,
            "-" => a - b,
            "*" => a * b,
            "/" => b != 0 ? a / b : double.NaN,
            _ => 0
        };
 
        if (double.IsNaN(result))
        {
            Console.WriteLine("错误：除数不能为0");
            return;
        }
 
        string record = $"{a} {op} {b} = {result}";
        history.Add(record);
        Console.WriteLine($"结果: {result}");
    }
 
    static void ShowHistory()
    {
        if (history.Count == 0)
        {
            Console.WriteLine("暂无历史记录");
            return;
        }
 
        Console.WriteLine("\n=== 历史记录 ===");
        for (int i = 0; i < history.Count; i++)
        {
            Console.WriteLine($"{i + 1}. {history[i]}");
        }
    }
 
    static void ClearHistory()
    {
        history.Clear();
        Console.WriteLine("历史记录已清除");
    }
}

dotnet run