binarySearch(A, n, num)

This function find number in array (sorted) using binary search

Syntax: [index] = binarySearch(A, n, num);
Inputs: A: Array (sorted) that you want to search
n: Length of array A
num: Number you want to search in array A
Outputs: index: Return position in A that A(index) == num or -1 if num does not exist in A
Complexity: O(1) best-case performance
O(log_2 (n)) worst-case performance
O(1) auxiliary space
Author: Trong Hoang Vo
[e-mail]
Date: March 31, 2016