Logic error with C# if statement but I'm unsure why

Question

I am just starting to learn C# in college and I was tasked with making a console program that acts as a maths quiz, with my if statements it only outputs correct even if the user inputs an incorrect answer, I can't figure out why, I've looked at multiple websites but everything seems to be fine with the code? I was hoping someone here with more experience would be able to help.

Below is the code but I can't figure out what's wrong with it, like I said before I looked over multiple websites and my code seems to be in line with what they were doing, my teacher also had a glance at it but couldn't see any faults

// we need to make a maths quiz..

using System;

namespace MathsQuiz
{
    internal class Program
    {
        private static Random GetRandom()
        {  
            return new Random(); 
        }
        
        static void Main(string[] args)
        {
            //this is where the random numbers are generated
           Random random = GetRandom();
            int num1 = random.Next(1, 100);
            int num2 = random.Next(1, 100);

            int answer = num1 + num2;

            /*this shows the user the question using
            the randomly generated numbers*/
            Console.WriteLine("Welcome to the maths quiz!\nWe still start with addition,\n add these following numbers\n" + num1 + "+" + num2 + "=   ?");


            int UserAnswer = Convert.ToInt32(Console.ReadLine());

            //checks if the users answer is correct

            if (Convert.ToBoolean(UserAnswer = answer))
            {
                Console.WriteLine("Correct!");
            }
            else if (Convert.ToBoolean(UserAnswer != answer))
            {
                Console.WriteLine("Incorrect.");
            }
        }
    }
}

Answer 1

As some comments already state:

• no need for the Convert.ToBoolean
• '=' is not a logical comparison operator
• as it can be either 'true' or 'false' -> no need for two ifs at all
• recommend to have lower case namings for variables

So adjust your code to look like this:

if (userAnswer == answer) 
{ /* correct answer */ 
} 
else 
{ /* incorrect answer */ 
}

Answer 2

You are using the assignment operator = instead of the equals operator ==. The result of an assignment expression is the assigned value. This means that UserAnswer = answer replaces the UserAnswer by answer. This results in whatever integer value answer is and not in true or false.

The value of answer is then converted to a Boolean which is independent of the the user's answer.

The result of a comparison with == or != or any other comparison operator like > is a Boolean, so no explicit type conversion is required.

The if statement should be like this instead:

if (UserAnswer == answer) ...

Another point is that the if statement processes the true case and the else statement the false case. I.e., else automatically handles the "Incorrect" case. No further if is required.

if (UserAnswer == answer)
{
    Console.WriteLine("Correct!");
}
else
{
    Console.WriteLine("Incorrect.");
}