In this algorithm it is trying to guess your number. Where it says set upper and lower to 0 and 127 its basically saying when you start a new game it will clear up the numbers from upper and lower. It will keep guessing and estimating your number by saying is it more than....... While you press n and y it will delete all the numbers that you have said because you have said its more than this or its not more than this.......
Write something about yourself. No need to be fancy, just an overview.