Who can help me with my HomeWork?

I was dong my C# HomeWork when I fell on a little problem.
I can't fix it my self..
Who can help me with my HomeWork?
The Error I'll get with the code under here..
Use of unassigned local variable 'ValidKey'

Code:

---

using System;
using System.Collections.Generic;
using System.Text;

namespace Huiswerk
{
    class Program
    {
        static void ShowProfile()
        {
            Console.WriteLine("Hello World..");
        }

        static void Say(string Input)
        {
            Console.WriteLine(Input);
        }

        static void Main(string[] args)
        {
            //Declaration of Variables
            string ValidKey;
            int RandomKey = 1;
            string TempStr;
            //Start Program
            Say("Type the Following Text: ");

            switch (RandomKey)
            {
                case '1':
                    ValidKey = "qwerty";
                    break;
                case '2':
                    ValidKey = "hello";
                    break;
                case '3':
                    ValidKey = "enter";
                    break;
            }
            Say(ValidKey);
            TempStr = Console.ReadLine();
            if (TempStr == ValidKey)
            {
                Say("Welcome User..\n\t Please Enter..");
                //Show Profile
                ShowProfile();
            }
            else
            {
                Say("Invalid!!");
            }
        }
    }
}

---

thx already

1) RandomKey is of type int, so remove the ''s from the case keyword

Code:

---

case 1:
  ValidKey = "qwerty";
  break;

case 2:
  ValidKey = "hello";
  break;

case 3:
  ValidKey = "enter";
  break;

---

since you are using Switch statement to assign to a variable, it is always recommended to use a default or atlest initialise it with an empty string, so the Switch should look something like this:

Code:

---

//either initialise
//string ValidKey = null;
//or

switch (RandomKey)
{
    case 1:
        ValidKey = "qwerty";
        break;

    case 2:
        ValidKey = "hello";
        break;

    case 3:
        ValidKey = "enter";
        break;

    default:
        ValidKey = "";
        break;
}

---

hope it helps you.

Long switch constructs are almost always a sign of bad logic. Use an array instead, it's neater as you don't have to repeat so much code.

Code:

---

string ValidKey = (new string[3] {
  "qwerty",
  "hello",
  "enter"
})[RandomKey];

---

Quote:

---

Originally Posted by penagate

Long switch constructs are almost always a sign of bad logic. Use an array instead, it's neater as you don't have to repeat so much code.

Code:

---

string ValidKey = (new string[3] {
  "qwerty",
  "hello",
  "enter"
})[RandomKey];

---

---

:thumb: Never knew about it.

The actual reason that you're getting that error is because it is possible for your code to follow a path that does not assign a value to the ValidKey variable before it's used, which is illegal. Looking at this section of code:

Code:

---

            string ValidKey;
            int RandomKey = 1;
            string TempStr;
            //Start Program
            Say("Type the Following Text: ");

            switch (RandomKey)
            {
                case '1':
                    ValidKey = "qwerty";
                    break;
                case '2':
                    ValidKey = "hello";
                    break;
                case '3':
                    ValidKey = "enter";
                    break;
            }
            Say(ValidKey);

---

ignoring the fact that your case expressions are the wrong type, if RandomKey is not 1, 2 or 3 then ValidKey will not be assigned a value when you get to the line that calls Say(). The rules of C# dictate that all variables must have been assigned a value before appearing on the right-hand side of an assignment (read: equals sign) or in a parameter list. To fix this issue you must ensure that no matter what path of execution your code follows it will assign a value to ValidKey by that line. There are two ways that you'd consider doing this. You can either add a 'default' case to your switch statement or else just initialise the ValidKey variable to a value when you declare it. Note that null is a valid value. This is what you'd do if you know for sure that RandomKey will be either 1, 2 or 3.

Quote:

---

Originally Posted by penagate

Long switch constructs are almost always a sign of bad logic. Use an array instead, it's neater as you don't have to repeat so much code.

Code:

---

string ValidKey = (new string[3] {
  "qwerty",
  "hello",
  "enter"
})[RandomKey];

---

---

I had to Include a Switch so thats why I did it this way...

Thank you all..

You see that alot... Someone needs help with homework, you look at it and say you could do this part here in a "much more compact and robust manner" and they look at you and say but I have to use that - it's part of the assignment. ARGG!! Dang teachers and their required constructs! :D