C# Error CS1040 – Preprocessor directives must appear as the first non-whitespace character on a line

C# Error

CS1040 – Preprocessor directives must appear as the first non-whitespace character on a line

Reason for the Error & Solution

Preprocessor directives must appear as the first non-white-space character on a line

A was found on a line and was not the first token on the line. A directive must be the first token on the line.

The following sample generates CS1040:

// CS1040.cs  
/* Define a symbol, X */ #define X   // CS1040  
  
// try the following two lines instead  
// /* Define a symbol, X */  
// #define X  
  
public class MyClass  
{  
   public static void Main()  
   {  
   }  
}