How to press enter for a menu without the enter being used for the next operation

Question

So, I am learning C#, and to practice, I have been trying to make a math solver, so the way I did it, is 1- I present the math question, 2- I receive user-input of the solution, 3- I compare the user's answer to my answer using an if statement, now, I am trying to add a console menu to add different divisions (multiplication/division/sub./add.), i have successfully added the menu, however I am not able to move onto inputting the numbers, the error I get is http://prntscr.com/ohru2i , how can I fix it?

I have tried putting Console.clear(), I have also tried to use break;, but none of them worked

using Figgle;
using System; 
using System.Threading;

public class MainClass
{
    public static void Main()
    {
        Console.Title = $"The Math Solver | Correct = 0 | Wrong = 0";
        char choice;

        for (; ; )
        {
            do
            {
                Console.WriteLine("Choose Method:");
                Console.WriteLine("  1. Multiplication");
                Console.WriteLine("  2. Division");
                Console.WriteLine("  3. Addition");
                Console.WriteLine("  4. Subtraction");
                Console.WriteLine("  5. Find the Remainder");
                Console.WriteLine("Press Q to Exit ");
                do
                {
                    choice = (char)Console.Read();
                } while (choice == '\n' | choice == '\r');
            } while (choice < '1' | choice > '5' & choice != 'q');

            if (choice == 'q') break;

            Console.WriteLine("\n");
            Console.Clear();
            switch (choice)
            {
                case '1':
                    {
                        Console.WriteLine(
                        FiggleFonts.Standard.Render("Multiplication"));

                        int milliseconds2 = 2000;
                        Thread.Sleep(milliseconds2);

                        int correctAnswers = 0;
                        int WrongAnswers = 0;
                        int Number1;
                        int Number2;
                        int myInt2;
                        while (true)
                        {
                            Console.WriteLine("Write the first number to multiply");
                            Number1 = int.Parse(Console.ReadLine());
                            Console.WriteLine("Write the second number to multiply");
                            Number2 = int.Parse(Console.ReadLine());
                            Console.WriteLine($"Write the answer of {Number1} * {Number2}");
                            myInt2 = int.Parse(Console.ReadLine());

                            if (myInt2 == Number1 * Number2)
                            {
                                Console.WriteLine(
                                FiggleFonts.Standard.Render("Correct!"));
                                correctAnswers++;
                                Console.Title = $"The Math Solver | Correct = {correctAnswers} | Wrong = {WrongAnswers}";
                            }
                            else
                            {
                                Console.WriteLine(
                                FiggleFonts.Standard.Render("Wrong"));
                                WrongAnswers++;
                                Console.Title = $"The Math Solver | Correct = {correctAnswers} | Wrong = {WrongAnswers}";
                            }
                            int milliseconds3 = 2000;
                            Thread.Sleep(milliseconds3);
                            Console.Clear();
                        }
                    }
        }
    }
}

The error message I get is http://prntscr.com/ohru2i

Answer 1

You're getting the error when converting a number to a string because console.Read() consumes the first character from the standard input, but leaves the line break from the user hitting enter. Therefore, the next time you go to read a line from the console, you just get a blank line, which is not a valid string for number conversion.

Solution is to use Console.ReadLine() and either look at the first character by indexing the string, or replace choice character constants with string constants.