Reverse the array

Write a program to reverse an array or string

Given an array (or string), the task is to reverse the array/string.
Examples : 
 

Input  : arr[] = {1, 2, 3}
Output : arr[] = {3, 2, 1}

Input :  arr[] = {4, 5, 1, 2}
Output : arr[] = {2, 1, 5, 4}

Iterative way :
 
1) Initialize start and end indexes as start = 0, end = n-1 
2) In a loop, swap arr[start] with arr[end] and change start and end as follows : 
start = start +1, end = end – 1
Time Complexity : O(n)
Recursive Way :
 
1) Initialize start and end indexes as start = 0, end = n-1 
2) Swap arr[start] with arr[end] 
3) Recursively call reverse for rest of the array.