data structure question

I'm not sure what this is called, I forget the name of this searching method, all i need is the name and a link with information on a searching method like this:

 supose you have a sorted array.
 suppose you want to search this array for an element.

 Here is psuedocode:
 
  int myArray[] = {1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17};
  int start = 0;
  int end = 16;
  int search = 3;
  int found = -1;

do
{
 if ( myArray[ (start - end) / 2 ] < search )
    start = (start - end) / 2 + 1;
 else if ( myArray[ (start - end) / 2] == search)
    found = (start - end) / 2;
 else
    end = (start - end) / 2 - 1;

} loop while (start != end && found == -1);

This is kind of like a "Divide and Conqour" approach, but what is this called? I remember studying something like this in a data structures class.




-Brian