A simple question of methods

Question

Hi all I am teaching myself C# and have a simple problem. The compiler displays an error message for the code (below). I have spent hours trying to figure out why it won't compile and hope one of you very knowledgeable programmers will tell me what is wrong. Thank-you in advance Terry --------------SOURCE CODE & COMPILER ERROR BELOW---------------- // Line 4 using System; public class a_String { public static void Main() { string aString; string strAdded; string firstStr = ABC; // L15 Console.Out.Write(Enter the letter after  + firstStr); aString = letter(strAdded); Console.Out.WriteLine(You entered the letter  + aString); // L20 } // end Main // L24 public static string letter(string input) { string theLetter; theLetter = Console.ReadLine(); return theLetter; } } // end class a_String // L32 // ----- COMPILER ERRORS ----- // PassStr.cs(1724): error CS0165: Use of unassigned local variable 'strAdded'

Vulpes · Answer

Unlike many other programming languages local variables in C# don't have a default value and must therefore be given a value before they are used. In particular if you pass a local variable as an argument to a method you must give it a value first. The only exceptions to this are 'out' parameters - something which you might not have come across yet. So when the C# compiler sees you passing strAdded to the letter method it complains that it's 'unassigned'. Bala's solution deals with that problem by assigning an empty string to it. It doesn't actually matter (but does no harm) if you assign a value to aString or not because the compiler can see that it's being assigned a value a few lines down before you use it. However one other thing I've noticed is that you don't actually use the 'input' parameter in the letter method anyway and could therefore get rid of the strAdded variable altogether: using System; public class a_String { public static void Main() { string aString; string firstStr = ABC; Console.Out.Write(Enter the letter after  + firstStr); aString = letter(); Console.Out.WriteLine(You entered the letter  + aString); } // end Main public static string letter() { string theLetter; theLetter = Console.ReadLine(); return theLetter; } } // end class a_String

Terry Bockman · Answer

That is good info! It helps explain a lot. Thank-you! Terry :)

Terry Bockman · Answer

Sorry to get back to you so late; been on vacation. I tried your correction and it works! Thanks for the help Terry

Marish Balasubramanian · Answer

change the declaration as follows string aString=; string strAdded=;