为什么我的数组包含我从未添加过的整数?C#

  int gameTurns = 12;
        do
        {               
            gameTurns -= 1;
            Console.WriteLine("     You have " + (gameTurns) + " attempts left.");
            Console.WriteLine();            
            Console.WriteLine();
            string userEnteredPassword = "";
            Console.WriteLine("Enter a password of 4 digits ");
            userEnteredPassword = Console.ReadLine();
           for (int i = 0; i < numbersToGuess.Length; i++)
            {
                numbersFromPlayer[i] = Convert.ToInt16(userEnteredPassword[i]);                    
                Console.WriteLine(numbersFromPlayer[i]);
            }

注意，numbersToGuess是这样声明的：

 for (int i = 0; i <= 3; i++) 
        {
            numbersToGuess[i] = Convert.ToInt16(sequence.Next(9));
            Console.WriteLine(numbersToGuess[i]);
        }

当我使用以下值运行代码时：1、2、3、4，它打印：49，50，51，52。