Q:

What have I done wrong with this loop?

This code should fully loop when it's run, without the loop it runs perfectly fine, but when I've added my loop the first part works fine, but then when you enter another number it shows the exact same result as before and it never changes, nor does it end when it's supposed to. It may seem like a stupid thing but I'm new to this. Am I using the wrong kind of loop?
    using System;

    class FizzBuzz
    {
    //Global variables
    int fizzCount;
    int buzzCount;
    int fizzbuzzCount;
    int primeCount;

    public bool IsFizz(int input)
    {
        if (input % 9 ==0)
        {
            fizzCount++; //Add 1 to fizzCount
            return true;
        }
        else
        {
            return false;
        }
    }
    public bool IsBuzz(int input)
    {
        if (input % 13 ==0)
        {
            buzzCount++; //Add 1 to buzzCount
            return true;
        }
        else
        {
            return false;
        }
    }

    public bool IsFizzBuzz(int input) 
    {
        if ((input % 13 ==0) && (input % 9 ==0))
        {
            fizzbuzzCount++; //Add 1 to fizzbuzzCount
            return true;
        }
        else
        {
            return false;
        }
    }

    public bool IsPrime(int input)
    {
        for(int i = 2; i < input; i++)
        {
            if (input % i ==0)
            {
                return false;
            }
        }

        primeCount++; //Add 1 to primeCount
        return true;
    }

    public void BeginTesting() 
    {
        fizzCount = 0; //Resets fizzCount
        buzzCount = 0; //Resets buzzCount
        fizzbuzzCount = 0; //Resets fizzbuzzCount
        primeCount = 0; //Resets primeCount         
    }       

    public int TotalFizz()
    {
        return fizzCount; 
    }
    public int TotalBuzz()
    {
        return buzzCount;
    }
    public int TotalFizzBuzz()
    {
        return fizzbuzzCount;
    }
    public int TotalPrime()
    {
        return primeCount;
    }

    public static void Main()
    {       
        Console.WriteLine("Please enter a number ");
        int input;
        string inputString;
        inputString = Console.ReadLine();
        input = int.Parse(inputString);
        while(input !=0) 
        {

            FizzBuzz fizzbuzz = new FizzBuzz();

            Console.WriteLine("IsFizz " + fizzbuzz.IsFizz(input)); //Shows if IsFizz is true or false
            Console.WriteLine("IsBuzz " + fizzbuzz.IsBuzz(input)); //Shows if IsBuzz is true or false
            Console.WriteLine("IsFizzBuzz " + fizzbuzz.IsFizzBuzz(input)); //Shows if IsFizzBuzz is true or false
            Console.WriteLine("IsPrime " + fizzbuzz.IsPrime(input)); //Shows if IsPrime is true or false
            Console.WriteLine("Fizz Count total is " + fizzbuzz.TotalFizz()); //Shows the total amount of Fizz counters 
            Console.WriteLine("Buzz Count total is " + fizzbuzz.TotalBuzz()); //Shows the total amount of Buzz counters 
            Console.WriteLine("FizzBuzz Count total is " + fizzbuzz.TotalFizzBuzz()); //Shows the total amount of FizzBuzz counters 
            Console.WriteLine("Prime Count total is " + fizzbuzz.TotalPrime());
            Console.WriteLine("Please enter another number or press 0 to exit");//Shows the total amount of Prime counters 
            inputString = Console.ReadLine();

        }   
    }   
}

A:

Convert you inputString to a int and set it to input variable.
while(input !=0) 
{
    FizzBuzz fizzbuzz = new FizzBuzz();

    Console.WriteLine("IsFizz " + fizzbuzz.IsFizz(input)); //Shows if IsFizz is true or false
    Console.WriteLine("IsBuzz " + fizzbuzz.IsBuzz(input)); //Shows if IsBuzz is true or false
    Console.WriteLine("IsFizzBuzz " + fizzbuzz.IsFizzBuzz(input)); //Shows if IsFizzBuzz is true or false
    Console.WriteLine("IsPrime " + fizzbuzz.IsPrime(input)); //Shows if IsPrime is true or false
    Console.WriteLine("Fizz Count total is " + fizzbuzz.TotalFizz()); //Shows the total amount of Fizz counters 
    Console.WriteLine("Buzz Count total is " + fizzbuzz.TotalBuzz()); //Shows the total amount of Buzz counters 
    Console.WriteLine("FizzBuzz Count total is " + fizzbuzz.TotalFizzBuzz()); //Shows the total amount of FizzBuzz counters 
    Console.WriteLine("Prime Count total is " + fizzbuzz.TotalPrime());
    Console.WriteLine("Please enter another number or press 0 to exit");//Shows the total amount of Prime counters 
    inputString = Console.ReadLine();

    // try to convert, if is not succedde, keep the original value (0).
    int.TryParse(inputString, out input);
}

