四則運算

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace 四則運算
{
    class Program
    {
        static void Main(string[] args)
        {
            int ans = 0;
            for (int i = 1; i < 11; i++)
            {
                Random rand = new Random(Guid.NewGuid().GetHashCode());
                int f = rand.Next(1, 5);
                int a=rand.Next(1,10);
                int b=rand.Next(1,10);
                int c;
                switch (f) {
                    case 1:
                        Console.Write("{0}、  {1}+{2}=",i,a,b);
                        c = Convert.ToInt32(Console.ReadLine());
                        if (c == a + b)
                        { Console.WriteLine("   T"); ans += 10; }
                        else
                            Console.WriteLine("   F");
                        break;
                    case 2:
                        Console.Write("{0}、  {1}-{2}=", i, a, b);
                        c = Convert.ToInt32(Console.ReadLine());
                        if (c == a - b)
                        { Console.WriteLine("   T"); ans += 10; }
                        else
                            Console.WriteLine("   F");
                        break;
                    case 3:
                        Console.Write("{0}、  {1}*{2}=", i, a, b);
                        c = Convert.ToInt32(Console.ReadLine());
                        if (c == a * b)
                        { Console.WriteLine("   T"); ans += 10; }
                        else
                            Console.WriteLine("   F");
                        break;
                    case 4:
                        Console.Write("{0}、  {1}/{2}=", i, a, b);
                        string str=(Console.ReadLine());
                        float d=float.Parse(str);//若+-*輸入小數報錯，也可以使用這方法避免程序中止
                        if (d == ((float)a / b))
                        { Console.WriteLine("   T"); ans += 10; }
                        else
                            Console.WriteLine("   F");
                        break;
                    default:
                        break;
                }
            }
            Console.WriteLine("得分：{0}", ans);
        }
    }
}