Give the recursive binary search algorithm.

What will be an ideal response?

The recursive binary search is sent an array and indices first and last that specify limits of the subarray. The function tests the condition first>last to determine whether the key is not present in the array. If true, report this and quit.

If the key may be present, a ‘middle’ index is computed, and the equality of the element at the middle is compared to the key. If equal, report this fact and quit.

If the key still may be present, determine if the key is in the upper or lower half of the array and recursively call the search on that half array.