Question

在使用TryParse捕获用户是否在何处输入字符串而不是int时，我的代码无法正常工作。如果我按现在的样子使用它，则仅当输入了除int之外的其他值时，我的基本值才为0。我希望它向用户显示错误消息。

尝试过尝试使用TryParse的多种不同方法，但没有一种真的有用。

    static void Main(string[] args)
    {

        Random r = new Random();
        int speltal = r.Next(1,21);
        bool play = false;
        int myNum;

        while (!play)
        {
            Console.Write("\n\tGuess a number between 1 and 20: ");
            Int32.TryParse(Console.ReadLine(), out myNum);

            if (myNum < guessNum)
            {
                Console.WriteLine("\tThe number you have guessed is to low");
                Console.ReadLine();
            }

            if (myNum > guessNum)
            {
                Console.WriteLine("\tThe number you have guessed is to high");
                Console.ReadLine();
            }

            if (myNum == guessNum)
            {
                Console.WriteLine("\tCongratulations you guessed the right number!");
                Console.ReadLine();
            }

如果用户输入除int以外的任何内容，我希望它向用户显示错误消息。根据我的老师，还必须包括TryParse

Answer 1

您没有捕获bool的{{1}}输出，因此您不知道是否输入了非数字值。尝试这样的事情：

TryParse

Answer 2

TryParse方法只能将整数放在传递的变量中（因为它是int类型），因此，如果传递给它的值不能解析为整数，则默认值为int（0）中的分配给变量。

TryParse告诉您是否成功解析了数字的方法是返回布尔值指示符。

您可以尝试以下方法：

while (true)
{
    bool valid = int.TryParse(Console.ReadLine(), out myNum);
    if(valid)
        break;
    Console.WriteLine("Input invalid. Please try again");
}

Answer 3

您应该使用bool返回的TryParse。看起来像这样：

更新的答案：

        static void Main(string[] args)
        {
            Random random = new Random();
            int guessNum = random.Next(1, 21);

            while(true)
            {
                Console.WriteLine("Guess the number between 1 and 21.");

                if (Int32.TryParse(Console.ReadLine(), out int input))
                {
                    if (input == guessNum)
                    {
                        Console.WriteLine($"You guessed it right. The number is {input}");
                        if(ShouldContinue())
                        {
                            guessNum = random.Next();
                            continue;
                        }
                        else
                        {
                            break;
                        }
                    }

                    if (input < guessNum)
                        Console.WriteLine("The number you guessed is smaller.");
                    else
                        Console.WriteLine("The number you guessed is bigger");

                }
                else
                {
                    Console.WriteLine("Please enter a number between 1 and 21 as your guess");
                }
            }
        }

        static bool ShouldContinue()
        {
            while (true)
            {
                Console.WriteLine($"Do you want to continue playing? (y/n)");
                string continueInput = Console.ReadLine().Trim().ToLower();
                if (continueInput == "y")
                    return true;
                else if (continueInput == "n")
                    return false;
                else
                    Console.WriteLine("Invalid input!. Please choose 'y' or 'n'.");
            }
        }

旧答案：

while (true)
{
    if (Int32.TryParse(inputInt, out int myNum))
    {
       // your logic goes here, too low/high or correct answer.   
    }
}

Answer 4

TryParse返回一个布尔值，该布尔值指示输入字符串是否已成功解析。上面的两个答案在如何处理无效输入方面都是正确的，但是，这是一个更干净的版本，它还将支持规则，between 1 and 20：

while (true)
{    
    Console.Write("\n\tGuess a number between 1 and 20: ");

    //Checks to see if the input was successfully parsed to a integer also, performs a Trim on the input as to remove any accidental white spaces that a user might have typed in, e.g. "1000 "
    if (int.TryParse(Console.ReadLine().Trim(), out myNum))
    {
        //Checks to see if the parsed number is in the specified range
        if ((myNum > 0) && (myNum < 21))
        {
            break;
        }
        Console.WriteLine("\tThe input number was out of the specified range.");
    }
    else
    {
        Console.WriteLine("\tFailed to parse the input text.");
    }
    //Optional, makes the thread sleep so the user has the time to read the error message.
    Thread.Sleep(1500);

    //Optional, clears the console as to not create duplicates of the error message and the value of Console.Write
    Console.Clear();
}

// Continue here, if (myNum < guessNum) . . .

使用TryParse的数字猜谜游戏

4 个答案: