In this section we will illustrate some of LINGO’s programming features by developing a model to perform a binary search.  Binary searches are an efficient way to look up a key in a sorted list.  In the worst case, a binary search should perform no more than log2( n) comparisons to determine if a key is on a sorted list, where n is the number of items on the list.

The basic idea behind a binary search is that you bracket the key in the list.  You then iterate by reducing the size of the bracket by a factor of 2 each pass.  This process continues until you either find the key, or conclude that the key is not on the list when the bracket size becomes 0.