Binary search

Binary search is a neat algorithm that finds a certain key in an array of keys in a dictionary.  We have already been introduced to this in CSC108 and it is refreshing to come across something familiar every now and then.  However, my knowledge as it turns out is very basic.  The example we did in class was a little confusing but I think after writing it down on paper it has become much clearer.   From now on, pen and paper it is!