Search⌘ K
AI Features
Home
Courses
Recursion for Coding Interviews in C++

Solution Review 1: Let's Find the Total Number of Vowels

Explore how to count vowels in a string using recursion in C++. This lesson helps you understand the structure of a recursive function, including base and recursive cases, and how to process string characters effectively. By mastering this example, you will enhance your ability to solve string manipulation problems with recursion.

We'll cover the following...

Solution: How many vowels were there?

C++
#include <iostream>
#include <string>
using namespace std; 
int totalVowels(string text, int len, int index) 
{ 
  //Write your code here
  int count=0;
  if (len==0){return 0;}
  char single=toupper(text[index]);
  if(single=='A' || single=='E' || single=='I' || single=='O' || single=='U')  
  {  
    count++;
  }
    return count + totalVowels(text,len-1,index+1);
} 
//Function to test your code
int main(){
  cout<<"The string is: Hello World"<<endl;
  cout<<"The total number of vowels in this string are: "<<totalVowels("Hello World",10,0)<<endl;
  cout<<"The string is: STR"<<endl;
  cout<<"The total number of vowels in this string are: "<<totalVowels("STR",3,0)<<endl;
  cout<<"The string is: AEIOUaeiouSs"<<endl;
  cout<<"The total number of vowels in this string are: "<<totalVowels("AEIOUaeiouSs",12,0)<<endl;
}

Understanding the Code

Every recursive code has two functions; the recursive function and the main function.

Driver Function

The recursive function is called within the driver function so lets first look at what it does, from line 20 to 31.

  • There are three calls made to the recursive function and for each call, it prints the given string and the total number
...