title: How to check if first character of a string is a letter c#
body: <p>i need some help. I have to write a programm where you can do some calculation with matrices. </p>
  
  <p>The User input should be for example: A=[1,2,3;4,5,6;7,8,9]</p>
  
  <p>The user should be able to save up to 10 matrices. The user should be able to write operations like A+B or C*D</p>
  
  <p>I want to check, if the first character of the users input is a letter, if not, i want to give an exception. Is there a method in c# where you can check if the first character is a letter.  I want to save the letters into a string array so I can reference the name of the matrices to the int [,] which contains the matrices. Here is a snippet of my code:</p>
  
  <pre><code>int i = 0;
  int[][,] ArrayContainer = new int[10][,];
  int rowcount;
  int columncount;
  
  while (i &lt; 10)
  {
      string input = Console.ReadLine();
      string trimedinput; 
  
      if (input.Contains(" "))
      {
          trimedinput = input.Replace(" ", string.Empty);
      }
      else if (input == String.Empty)
      {
          break;
      }
      else if(!input.Contains("="))
      {
          Console.WriteLine("The definition of your matrix is not correct. Please     type in 'help' if you need help.");
          continue;
      }
      else
      {
          trimedinput = input;
      }
  }
  </code></pre>
  
  <p>Thank you for help!</p>