Program to count vowels in a string (Iterative and Recursive)

Given a string, count the total number of vowels (a, e, i, o, u) in it. There are two methods to count total number of vowels in a string. 

1. Iterative 
2. Recursive

Examples: 

Input : abc de
Output : 2

Input : geeksforgeeks portal
Output : 7

1. Iterative Method:

Below is the implementation: 

2

Time Complexity: O(n), where n is the length of the string
Auxiliary Space: O(1) 

2. Recursive Method:

Below is the implementation: 

2

Time Complexity: O(n), where n is the length of the string
Auxiliary Space: O(n), where n is the length of the string since the function is calling itself n times.

How Recursive Code Working.
 

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