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C# C# Basics (Retired) Perfect Variable Scope

Posted by David Oliver
David Oliver
4,958 Points

What am I doing wrong?

The question is this:

Compiling the below code currently produces the error: "The name 'output' does not exist in the current context". This error is the result of improper variable scoping.

The output variable is declared twice: once within the if statement's curly braces and again within the else statement's curly braces. Remember, variables in C# can only be used within the curly braces that they are declared within. The last line of code in this program, Console.WriteLine(output);, is attempting to use a variable named output, which doesn't exist outside of the if/else statement's curly braces.

To fix this error:

Declare the output variable just before the if statement and assign it to an empty string (i.e. "").
Remove the string data types from the output variables within the if/else statement's curly braces
Program.cs 
using System;

namespace Treehouse.CodeChallenges
{
    class Program
    {
        static void Main()
        {            
            string input = Console.ReadLine();
            string output = "";
            if (input == "quit")
            {

            }
            else
            {

            }

            Console.WriteLine(output);
        }
    }
}

3 Answers

Steven Parker
Steven Parker
231,248 Points
Steven Parker
Steven Parker
231,248 Points

When the instructions say "Remove the string data types...", they mean just remove the word "string".

Don't remove the entire statements!

Davit Tavadze
Davit Tavadze
614 Points
Davit Tavadze
Davit Tavadze
614 Points

using System;

namespace Treehouse.CodeChallenges { class Program { static void Main() {
string input = Console.ReadLine(); string output = "";

        if (input == "quit")
        {
            output = "Goodbye.";
        }
        else
        {
            output = "You entered " + input + ".";
        }

        Console.WriteLine(output);
    }
}

}

//this should be more correct i guess

Gancho Iliev
Gancho Iliev
10,264 Points
Gancho Iliev
Gancho Iliev
10,264 Points

As Steven Parker says just remove the word "string". Here is my code:

using System;

namespace Treehouse.CodeChallenges
{
    class Program
    {
        static void Main()
        {            
            string input = Console.ReadLine();
            string output = "";

            if (input == "quit")
            {
                 output = "Goodbye.";
            }
            else
            {
                 output = "You entered " + input + ".";
            }

            Console.WriteLine(output);
        }
    }
}