Programa para contar vocales en una string (Iterativo y Recursivo)

Dada una string, cuenta el número total de vocales (a, e, i, o, u) en ella. Hay dos métodos para contar el número total de vocales en una string. 

1. Iterativo 
2. recursivo

Ejemplos: 

Input : abc de
Output : 2

Input : geeksforgeeks portal
Output : 7

1. Método iterativo:

A continuación se muestra la implementación: 

// 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 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

# Python3 program to count vowels
# in a string
 
# Function to check the Vowel
def isVowel(ch):
    return ch.upper() in ['A', 'E', 'I', 'O', 'U']
 
# Returns count of vowels in str
def countVowels(str):
    count = 0
    for i in range(len(str)):
 
        # Check for vowel
        if isVowel(str[i]):
            count += 1
    return count
 
# Driver Code
 
# string object
str = 'abc de'
 
# Total number of Vowels
print(countVowels(str))
 
# This code is contributed
# by SamyuktaSHegde

// C# program to count vowels in a string
using System;
 
class GFG
{
 
    // Function to check the Vowel
    public static bool isVowel(char ch)
    {
        ch = char.ToUpper(ch);
        return (ch == 'A' || ch == 'E' ||
                ch == 'I' || ch == 'O' ||
                              ch == 'U');
    }
 
    // Returns count of vowels in str
    public static int countVowels(string str)
    {
        int count = 0;
        for (int i = 0; i < str.Length; i++)
        {
             
            // Check for vowel
            if (isVowel(str[i]))
            {
                ++count;
            }
        }
        return count;
    }
 
    // Driver code
    public static void Main(string[] args)
    {
         
        //string object
        string str = "abc de";
 
        // Total numbers of Vowel
        Console.WriteLine(countVowels(str));
    }
}
 
// This code is contributed by Shrikant13

<?php
// PHP program to count vowels in a string
 
// Function to check the Vowel
function isVowel($ch)
{
    $ch = strtoupper($ch);
    return ($ch =='A' || $ch =='E' ||
            $ch =='I' || $ch =='O' ||
            $ch =='U');
}
 
// Returns count of vowels in str
function countVowels($str)
{
    $count = 0;
    for ($i = 0; $i < strlen($str); $i++)
        if (isVowel($str[$i])) // Check for vowel
            ++$count;
    return $count;
}
 
// Driver Code
 
//string object
$str = "abc de";
 
// Total numbers of Vowel
echo countVowels($str) . "\n";
 
// This code is contributed
// by Akanksha Rai
?>

<script>
      // JavaScript program to count vowels in a string
 
      // Function to check the Vowel
      function isVowel(ch) {
        ch = ch.toUpperCase();
        return ch == "A" || ch == "E" || ch == "I" || ch == "O" || ch == "U";
      }
 
      // Returns count of vowels in str
      function countVowels(str)
      {
        var count = 0;
        for (var i = 0; i < str.length; i++)
          if (isVowel(str[i]))
           
            // Check for vowel
            ++count;
        return count;
      }
 
      // Main Calling Function
 
      // string object
      var str = "abc de";
 
      // Total numbers of Vowel
      document.write(countVowels(str));
      document.write("<br>");
       
      // This code is contributed by rdtank.
    </script>

2

Complejidad de tiempo: O(n), donde n es la longitud de la string
Espacio auxiliar: O(1) 

2. Método recursivo:

A continuación se muestra la implementación: 

// 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;
}

// 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

# Recursive Python 3 program to count the
# total number of vowels using recursion
 
# Function to check the Vowel
def isVowel(ch):
    return ch.upper() in ['A', 'E', 'I', 'O', 'U']
 
# to count total number of
# vowel from 0 to n
def countVovels(str, n):
    if (n == 1):
        return isVowel(str[n - 1]);
 
    return (countVovels(str, n - 1) +
                isVowel(str[n - 1]));
 
# Driver Code
 
# string object
str = "abc de";
 
# Total numbers of Vowel
print(countVovels(str, len(str)))
 
# This code is contributed
# by Akanksha Rai

using System;
 
// Recursive C# program to count the total
// number of vowels using recursion
public class GFG
{
 
    // Function to check the Vowel
    public static int isVowel(char ch)
    {
        ch = char.ToUpper(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
    public static int countVowels(string str, int n)
    {
        if (n == 1)
        {
            return isVowel(str[n - 1]);
        }
 
        return countVowels(str, n - 1) + isVowel(str[n - 1]);
    }
 
    // Main Calling Function
    public static void Main(string[] args)
    {
        //string object
        string str = "abc de";
 
        // Total numbers of Vowel
        Console.WriteLine(countVowels(str,str.Length));
    }
}
 
// This code is contributed by Shrikant13

<?php
// Recursive PHP program to count the total
// number of vowels using recursion
 
// Function to check the Vowel
function isVowel($ch)
{
    $ch = strtoupper($ch);
    return ($ch == 'A' || $ch == 'E' ||
            $ch == 'I' || $ch == 'O' ||
            $ch == 'U');
}
 
// to count total number of
// vowel from 0 to n
function countVovels($str, $n)
{
    if ($n == 1)
        return isVowel($str[$n - 1]);
 
    return countVovels($str, $n - 1) +
               isVowel($str[$n - 1]);
}
 
// Driver Code
 
// string object
$str = "abc de";
 
// Total numbers of Vowel
echo countVovels($str, strlen($str)) . "\n";
 
// This code is contributed
// by Akanksha Rai
?>

<script>
 
// Recursive JavaScript program to count the total
// number of vowels using recursion
 
// Function to check the Vowel
function isVowel(ch)
{
    ch = ch.toUpperCase();
    return (ch=='A' || ch=='E' || ch=='I' ||
                        ch=='O' || ch=='U');
}
 
// to count total number of vowel from 0 to n
function countVovels(str,n)
{
    if (n == 1)
        return isVowel(str[n-1]);
 
    return countVovels(str, n-1) + isVowel(str[n-1]);
}
 
// Main Calling Function
 
// string object
let str = "abc de";
 
// Total numbers of Vowel
document.write(countVovels(str, str.length));
 
// This code is contributed by shinjanpatra
 
</script>

2

Complejidad de tiempo: O(n), donde n es la longitud de la string
Espacio auxiliar: O(n), donde n es la longitud de la string ya que la función se llama a sí misma n veces.

Cómo funciona el código recursivo.
 

Este artículo es una contribución de Prakhar Agrawal . Si te gusta GeeksforGeeks y te gustaría contribuir, también puedes escribir un artículo usando write.geeksforgeeks.org o enviar tu artículo por correo a review-team@geeksforgeeks.org. Vea su artículo que aparece en la página principal de GeeksforGeeks y ayude a otros Geeks.