Question

Ok what I am trying to do seems fairly simple, yet it’s not working the way I want it. I know I’m just not getting something. Essentially I am trying to read console input, assign it to a variable. Then I want to check that variable to see if it is a valid number. If it’s not, I want to tell the user it is invalid and start the loop over again until I get a valid number, then exit. Here is my code, can you please help me understand what I am doing wrong?

    const int AVERAGE_IQ = 100;
    int userIQ;
    bool done = false;

    do
    {
        Console.Write("Please enter an IQ Score between 1 and 200: ");
        userIQ = Convert.ToInt32(Console.ReadLine());

        if (userIQ == 0 || userIQ >= 200)
        {
            Console.WriteLine("You have entered an invalid IQ Score, please try again.");
            done = false;
        }
        else if (userIQ >= AVERAGE_IQ)
        {
            Console.WriteLine("{0} is an above average IQ.", userIQ);
            done = true;
            break;
        }
        else if (userIQ <= AVERAGE_IQ)
        {
            Console.WriteLine("{0} is an below average IQ.", userIQ);
            done = true;
            break;
        }
        else if (userIQ == AVERAGE_IQ)
        {
            Console.WriteLine("{0} is anaverage IQ.", userIQ);
            done = true;
            break;
        }

    } while (done =! true);

Answer 1

=! should be !=

You’re doing an assignment, setting done to false. Since:

while (done =! true); is the same as while (done = !true); which is the same as while (done = false);

On each iteration, you’re assigning done to be false, which itself evaluates to false, which means your loop will never iterate a second time.

Change the loop expression to either while (done != true); or better yet while (!done);