Question

I’m making a program that has little programs inside of it, and I’ve come to a dilemma. On my first mini-program which rearranges digits to find the greatest possible number from those digits, it asks if the user wants to quit. If they respond “Yes” then the function returns 0 which is evaluated in the main(string[] args) method. My problem is that whenever the user says “No”, the mini-program still doesn’t continue. Here’s my source:

    namespace ACSL_Competition
    {
        class Program
        {
    static int DigitRearranger()
    {
        string[] mainString = {};
        Console.WriteLine("---------Welcome to the Digit Re-arranger!---------");
        Console.WriteLine("I take a positive number up to 10000, and find the highest number that can be made out of its digits.");
        Console.WriteLine("Instructions: Enter a number up to 10000, and see the results!");
        drLabel:
        Console.Write("Your Number: ");

        string input = Console.ReadLine();
        int inputNumber = 0;
        try { inputNumber = int.Parse(input); }
        catch (Exception ex) { Console.WriteLine("Error: {0}", ex.Message); goto drLabel; }

        /*Placeholder code for the moment*/Console.WriteLine(inputNumber.ToString());
        evaluate:
        Console.Write("Do you want to exit? Yes/No: ");
        if (Console.ReadLine().Equals("Yes"))
            return 1;
        else if (Console.ReadLine().Equals("No"))
        {
            goto drLabel;

        }
        else
        {
            return 1;
        }

    }
    static void Main(string[] args)
    {
        Console.WriteLine("Welcome to the ACSL Competition Program. Choose a program to begin:");
        Console.Write("\n\t");
        Console.WriteLine("1\tDigit Re-arranger");
        label:
        Console.Write("\nProgram: ");
        string input = Console.ReadLine();
        int number = 0;
        try { number = int.Parse(input); }
        catch (Exception ex) { Console.WriteLine("Error: {0}", ex.Message); goto label; }
        if (number == 1)
        {
            Console.WriteLine("\n");
            if (DigitRearranger() == 1)
            {
                goto label;
            }
            else if (DigitRearranger() != 1)
            {
                DigitRearranger();
            }
        }
        else if (!number.Equals(1))
        {
            Console.WriteLine("Not a valid program.");
            goto label;
        }
        //----------------
        Console.ReadLine();
    }
}

}

Answer 1

The underlying problem is that you’re calling readline twice. The first time it gets the entered value, i.e. Yes, the second time you call it there is no data to read so it returns “”. If you need to reuse the same input store it in a variable, i.e.

 string inputVal = Console.ReadLine();

I hate goto statements, maybe you could restructure your code in to a while loop, something like:

bool exit = false;
while(!exit)
{
    Console.Write("Your Number: ");
    //Your main code
    Console.Write("Do you want to exit? Yes/No: ");
    if(Console.ReadLine() != "No")
      exit = true;
}

In fact, you could get rid of the exit variable, just do while(true) and return if the user enters anything other than no.