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

1.4

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

C++

// C++ program to count vowels in a string
#include<iostream>
using namespace std;

// Function to check the Vowel
bool isVowel(char ch)
{
    ch = toupper(ch);
    return (ch=='A' || ch=='E' || ch=='I' ||
                       ch=='O' || ch=='U');
}

// Returns count of vowels in str
int countVowels(string str)
{
    int count = 0;
    for (int i=0; i<str.length(); i++)
        if (isVowel(str[i])) // Check for vowel
            ++count;
    return count;
}

// Main Calling Function
int main()
{
    //string object
    string str = "abc de";

    // Total numbers of Vowel
    cout << countVowels(str) << endl;
    return 0;
}

Java

// Java program to count vowels in a string
public class GFG {
       
    // Function to check the Vowel
    static boolean isVowel(char ch)
    {
        ch = Character.toUpperCase(ch);
        return (ch=='A' || ch=='E' || ch=='I' ||
                           ch=='O' || ch=='U');
    }
     
    // Returns count of vowels in str
    static int countVowels(String str)
    {
        int count = 0;
        for (int i = 0; i < str.length(); i++)
            if (isVowel(str.charAt(i))) // Check for vowel
                ++count;
        return count;
    }
     
    // Driver code
    public static void main(String args[])
    {
        //string object
        String str = "abc de";
     
        // Total numbers of Vowel
        System.out.println(countVowels(str));
    }
}
// This code is contributed by Sumit Ghosh


Output:

2

2. Recursive Method

C++

// Recursive C++ program to count the total
// number of vowels using recursion
#include<iostream>
using namespace std;

// Function to check the Vowel
bool isVowel(char ch)
{
    ch = toupper(ch);
    return (ch=='A' || ch=='E' || ch=='I' ||
                        ch=='O' || ch=='U');
}

// to count total number of vowel from 0 to n
int countVovels(string str, int n)
{
    if (n == 1)
        return isVowel(str[n-1]);

    return countVovels(str, n-1) + isVowel(str[n-1]);
}

// Main Calling Function
int main()
{
    // string object
    string str = "abc de";

    // Total numbers of Vowel
    cout << countVovels(str, str.length()) << endl;
    return 0;
}

Java

// Recursive Java program to count the total
// number of vowels using recursion
public class GFG {
       
    // Function to check the Vowel
    static int isVowel(char ch)
    {
        ch = Character.toUpperCase(ch);
       if(ch=='A' || ch=='E' || ch=='I' ||
            ch=='O' || ch=='U') 
           return 1;
       else return 0;
    }
     
    // to count total number of vowel from 0 to n
    static int countVowels(String str, int n)
    {
        if (n == 1)
            return isVowel(str.charAt(n - 1));
     
        return countVowels(str, n-1) + isVowel(str.charAt(n - 1));
    }
     
    // Main Calling Function
    public static void main(String args[])
    {
        //string object
        String str = "abc de";
     
        // Total numbers of Vowel
        System.out.println(countVowels(str,str.length()));
    }
}
// This code is contributed by Sumit Ghosh


Output:

2

How Recursive Code Working..

This article is contributed by Prakhar Agrawal. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

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