83. Binary Search in Sorted Array

You are given a sorted array of n unsigned 8-bit integers (uint8_t) and a key to search. Your task is to:

• Perform a binary search to find the key
• Print the index of the key if found
• If not found, print -1 

Important:

• The array is guaranteed to be sorted in ascending order
• Use only loop-based (iterative) binary search — no recursion

Example-1

Input: n = 6, arr = [5 10 15 20 25 30], key = 20
Output: 3

Example-2

Input: n = 5, arr = [2 4 6 8 10], key = 1
Output: -1

Example-3

Input: n = 4, arr = [100 150 200 250], key = 250
Output: 3