C#在将用户输入放入数组之前检查用户输入答案

【问题标题】：C# Checking users input before placing it into an arrayC#在将用户输入放入数组之前检查用户输入
【发布时间】：2013-10-25 04:26:53
【问题描述】：

我希望用户输入 10 到 100 之间的 10 个数字，它们必须是唯一的，否则它会要求您输入一个新数字。我能够让数组工作并接受 10 个数字，但它不会检查它与其他数字或在我的值之间。在这段代码下面是我编写的一个有效但不是循环的代码。任何帮助表示赞赏。

    int a;
      int[] arr = new int[10]; // The size of the array is 10

      // Here the values are accepted from the user
      for (a = 0; a <= 9; a++)
      {
      Console.Write("\nEnter your number:\t");
      //Here is were all the storing is done
      arr[a] = Convert.ToInt32(Console.ReadLine());
      //Here is my check values for the inputted numbers
      if (arr[a] < 10 || arr[a] > 100)  // I tried using brackets and && nothing worked
      {
      // If they do not meet the correct information
      Console.WriteLine
      ("You did not enter a valid number.");
      --arr[a];

      }
      else
      {
      //When they do meet the correct values
      Console.WriteLine("Thanks for entering the number " + arr[a]);
      }
      }

      Console.WriteLine("\n");
      //Here the inputted values are printed out
      for (a = 0; a < 10; a++)
      {
      Console.WriteLine("You entered the number {0}", arr[a]);
      }
      Console.ReadLine();

我编写的有效代码不是循环。我正在尝试用更少的代码和循环来完成这个精确的代码。

            Console.WriteLine("Please enter 10 numbers between 10 and 100. They cannot be identical.");
            Retrypoint1:
            int a = int.Parse(Console.ReadLine());
            if ((a > 10) && (a < 100));

            else
            {
                Console.WriteLine("The number you entered does not fall between 10 and 100.\r\n Please try again.");
                goto Retrypoint1;
            }
            Retrypoint2:
            int b = int.Parse(Console.ReadLine());
            if ((b > 10) && (b < 100) && (b != a)) ;
            else
            {

                Console.WriteLine("The number you entered does not fall between 10 and 100 \r\n or is identical to one of the other numbers. Please try again");
                goto Retrypoint2;

            }
            Retrypoint3:
            int c = int.Parse(Console.ReadLine());
            if ((c > 10) && (c < 100) && (c != a) && (c != b)) ;
            else
            {
                Console.WriteLine("The number you entered does not fall between 10 and 100 \r\n or is identical to one of the other numbers. Please try again");
                goto Retrypoint3;
            }
            Retrypoint4:
            int d = int.Parse(Console.ReadLine());
            if ((d > 10) && (d < 100) && (d != a) && (c != b) && (d != c)) ;
            else
            {
                Console.WriteLine("The number you entered does not fall between 10 and 100 \r\n or is identical to one of the other numbers. Please try again");
                goto Retrypoint4;
            }
            Retrypoint5:
            int e = int.Parse(Console.ReadLine());
            if ((e > 10) && (e < 100) && (e != a) && (e != b) && (e != c) && (e != d)) ;
            else
            {
                Console.WriteLine("The number you entered does not fall between 10 and 100 \r\n or is identical to one of the other numbers. Please try again");
                goto Retrypoint5;
            }
            Retrypoint6:
            int f = int.Parse(Console.ReadLine());
            if ((f > 10) && (f < 100) && (f != a) && (f != b) && (f != c) && (f != d) && (f != e)) ;
            else
            {
                Console.WriteLine("The number you entered does not fall between 10 and 100 \r\n or is identical to one of the other numbers. Please try again");
                goto Retrypoint6;
            }
            Retrypoint7:
            int g = int.Parse(Console.ReadLine());
            if ((g > 10) && (g < 100) && (g != a) && (g != b) && (g != c) && (g != d) && (g != e) && (g != f)) ;
            else
            {
                Console.WriteLine("The number you entered does not fall between 10 and 100 \r\n or is identical to one of the other numbers. Please try again");
                goto Retrypoint7;
            }
            Retrypoint8:
            int h = int.Parse(Console.ReadLine());
            if ((h > 10) && (h < 100) && (h != a) && (h != b) && (h != c) && (h != d) && (h != e) && (h != f) && (h != g)) ;
            else
            {
                Console.WriteLine("The number you entered does not fall between 10 and 100 \r\n or is identical to one of the other numbers. Please try again");
                goto Retrypoint8;
            }
            Retrypoint9:
            int i = int.Parse(Console.ReadLine());
            if ((i > 10) && (i < 100) && (i != a) && (i != b) && (i != c) && (i != d) && (i != e) && (i != f) && (i != g) && (i != h)) ;
            else
            {
                Console.WriteLine("The number you entered does not fall between 10 and 100 \r\n or is identical to one of the other numbers. Please try again");
                goto Retrypoint9;
            }
            Retrypoint10:
            int j = int.Parse(Console.ReadLine());
            if ((j > 10) && (j < 100) && (j != a) && (j != b) && (j != c) && (j != d) && (j != e) && (j != f) && (j != g) && (j != h) && (j != i)) ;
            else
            {
                Console.WriteLine("The number you entered does not fall between 10 and 100 \r\n or is identical to one of the other numbers. Please try again");
                goto Retrypoint10;
            }
            Console.WriteLine("The numbers you entered were " + a + ", " + b + ", " + c + ", " + d + ", " + e + ", " + f + ", " + g + ", " + h + ", " + i + " & " + j);
            Console.WriteLine("Please press enter to continue");
            Console.ReadKey();

【问题讨论】：

您是否有特殊原因试图避免循环语句？
您不需要每次都循环检查数组中是否存在该数字。相反，使用Contains

标签： c# arrays loops

【解决方案1】：

问题出在这里：

 if (arr[a] < 10 || arr[a] > 100)  // I tried using brackets and && nothing worked
 {
 // If they do not meet the correct information
 Console.WriteLine
 ("You did not enter a valid number.");
 --arr[a];
 }

使用--arr[a]，您可以减少用户输入的值，也可以将其丢弃。你想写的是--a。

要检查用户是否输入了双倍数字，您可以通过添加 if(…) 来检查

 || arr.Take(a).Contains(arr[a])

【讨论】：

谢谢你，这让我发疯了！！！这两小块解决了一切。您真棒！感谢您的帮助

【解决方案2】：

你的问题在这里：

--arr[a];

您应该递减a，而不是数组中的值。试试这个：

a--;

【讨论】：

抱歉，我忘了回答“唯一”约束。您应该将 if 语句更新为：if ((arr[a] < 10 || arr[a] > 100 ) && !arr.Contains(arr[a])) 您可能需要包含对 System.Linq 的引用
!arr.Contains(arr[a]) 始终为 false，因为 arr 始终在位置 a 包含其元素。还要注意arr 有很多空槽，所以你必须防止它们被检查。
谢谢，我自己也注意到了 :) 应该是 arr.Where(i => i == arr[a]).Count() > 1。我没有费心检查空槽，因为它们被初始化为 0，这已经被 arr[a] < 10 捕获，但你是对的。在实际将值设置到数组中之前进行验证会好得多。

【解决方案3】：

一些问题，其中至少有两个已经被提及：

您的代码不会检查输入的文本是否实际上是数字。如果用户输入的内容不是数字，Convert.ToInt32 将抛出异常。
使用--arr[a]，您正在递减数组中a 位置的值，而不是a 的值。
不要在没有非常充分理由的情况下goto。即使在测试代码中。

这里有一些代码应该涵盖了您正在尝试做的大部分事情：

int[] arr = new int[10];

for (int a = 0; a < 10; )
{
    // Get number from user
    Console.Write("Enter number: ");
    string entered = Console.ReadLine();
    int val;

    // check for valid integer entered
    if (!Int32.TryParse(entered, out val))
        Console.WriteLine("Invalid number '{0}'", entered);
    // check number in allowed range
    else if (val < 10 || val > 100)
        Console.WriteLine("Value '{0}' out of allowed range (10-100)", val);
    // check number not already supplied
    else if (a > 0 && arr.Take(a).Contains(val))
        Console.WriteLine("Value '{0}' already entered");
    // add to array
    else
    {
        arr[a++] = val;
        Console.WriteLine("Added value '{0}'.  {1} remaining.", val, 10 - a);
    }
}

【讨论】：

所以你在第一个语句中的意思是我应该编写代码来接受输入，检查输入是否是一个数字，然后要么把它扔掉，要么继续检查？
如果您期待一个数字并且用户输入了一个非数字值 - 例如他们的名字 - 您的代码将在尝试将输入转换为数字期间死亡。例如，使用 TryParse 可以保护您免受这种情况的影响。

【解决方案4】：

这样的东西应该适合你，我正在使用 TryParse 过滤掉非数字字符和一个 do while 循环，我还使用 Contains Linq Extension method 来检查重复项。看看这是否适合你。

static void Main(string[] args)
{
    int[] arr = new int[10];
    int count = 0;
    int a;
    do
    {
        if (int.TryParse(Console.ReadLine(), out a)) //Verify that input is numeric
        {
            if ((a > 10) && (a < 100))  //Check Constraints
            {
                if (!arr.Contains(a))   //Check for duplicates
                {
                    arr[count] = a;    //Only if we get here then input into array
                    count++;           //Increment to next Index
                }
            }
        }
    } while (count < 10);             //Rinse and repeat to you get 10 valid entries

    Console.ReadLine();
}

【讨论】：

【解决方案5】：

您可以尝试以下进行更多验证（请参阅注释代码）：

static void Main(string[] args)
    {
        int[] arr = new int[10]; // The size of the array is 10
        int input;
        int savedNumCount = 0;
        const int MIN = 10;  // Use constant to set the range instead
        const int MAX = 100; // of typing them in code

        Console.WriteLine("Please enter 10 numbers between 10 and 100. They cannot be identical.");
        do
        {
            if (int.TryParse(Console.ReadLine(), out input) == false)
            { // Check if number is entered
                Console.WriteLine("Please enter a number.");
                continue;
            }
            if (input < MIN || input > MAX)
            { // Check range
                Console.WriteLine("The number you entered does not fall between 10 and 100.\r\n Please try again.");
                continue;
            }                
            if (savedNumCount == 0)
            { // Compare with existing numbers
                arr[savedNumCount] = input; // No checking for 1st input
                savedNumCount++;
            }
            else
            {
                if (!arr.Contains(input))
                {
                    arr[savedNumCount] = input;
                    savedNumCount++;
                }
                else
                {
                    Console.WriteLine("The number you entered is identical to one of the other numbers. Please try again");
                }
            }
        }
        while (savedNumCount < arr.Length);

        string result = "The numbers you entered were ";
        foreach (int num in arr)
            result += num.ToString() + "  ";
        Console.WriteLine(result);
        Console.WriteLine("Please press enter to continue");
        Console.ReadKey();
    }

【讨论】：

【解决方案6】：

我不希望首先存储无效输入：

Console.Write("\nEnter your number:\t");
int input = Convert.ToInt32(Console.ReadLine());
if (input < 10 || input > 100 || arr.Contains(input))
    Console.WriteLine("You did not enter a valid number.");
else
{
    arr[a] = input;
    //When they do meet the correct values
    Console.WriteLine("Thanks for entering the number " + arr[a]);
}

【讨论】：