Code:
using System;
using System.Collections.Generic;
using System.Text;

namespace _._
{
    class Program
    {
        static void Main(string[] args)
        {
            while (true)
            {
                int randomNumber = GenerateNumber(1, 21);
                int counter = 1;
                while (true)
                {
                    Console.Write("Enter a number between 1 and 20(0 to quit):");
                    int input = Convert.ToInt32(Console.ReadLine());

                    if (input == 0)
                        return;
                    else if (input < randomNumber)
                    {
                        Console.WriteLine("Too low, try again.");
                        ++counter;
                        continue;
                    }
                    else if (input > randomNumber)
                    {
                        Console.WriteLine("Too high, try again.");
                        ++counter;
                        continue;
                    }
                    else
                    {
                        Console.WriteLine("You guessed it! The number was {0}!", randomNumber);
                        if (counter == 1)
                            Console.WriteLine("And you guessed it right away! Bonus points!\n");
                        else
                            Console.WriteLine("It took you {0} {1}.\n", counter, counter == 1 ? "try" : "tries");
                        break;
                    }
                }
            }

        }
        static int GenerateNumber(int min, int max)
        {
            Random random = new Random();
            return random.Next(min, max);
        }
    }
}
This code is for a guessing game, the user inputs a number and the computer states if its right or wrong

no I got the basics but I need to do more, I need an option to ask the user how many games he wants, and to only allow the user 6 tries before he or she loses, also I need the numbers in the range to get smaller and smaller after each guess

im so stuck on this, any help would be great
I tried
Code:
if (counter == 6)
                        Console.WriteLine("You have attempted 6 times, you lost");
                    break;
and that didnt work

also tried
Code:
int guess = 0;
     for( guess = 0; guess < 6; guess++ )
     {
           .
           .
           .
           if( input == random )
             break;
     }
     if( guess < 6 )
        Console.WriteLine("It took you {0} {1}.\n", guess+1, (guess + 1) == 1 ? "try" : "tries");
     else
        Console.WriteLine("You lost.");
and that didnt work either