Count the Number of Vowels in a Given String

This program counts the number of vowels in a given string using C++.

Program Explanation

The program structure includes:

• Input: A string entered by the user.
• Process: Iterates through the string to count vowels.
• Output: Displays the number of vowels in the string.

C++ Program

/**
 * Program to count the number of vowels in a given string.
 * 
 * This program reads a string from the user and counts the number
 * of vowels (a, e, i, o, u) in the string, regardless of case.
 */

#include <iostream>
#include <string>

using namespace std;

// Function to count vowels in a given string
int countVowels(const string& str) {
    int count = 0;
    for (char ch : str) {
        // Convert character to lowercase for case insensitivity
        char lowerCh = tolower(ch);
        // Check if the character is a vowel
        if (lowerCh == 'a' || lowerCh == 'e' || lowerCh == 'i' || lowerCh == 'o' || lowerCh == 'u') {
            count++;
        }
    }
    return count;
}

int main() {
    string inputString;
    
    // Prompt user for input
    cout << "Enter a string: ";
    getline(cin, inputString);
    
    // Count the number of vowels in the input string
    int vowelCount = countVowels(inputString);
    
    // Output the result
    cout << "Number of vowels in the given string: " << vowelCount << endl;
    
    return 0;
}

Documentation

Function: countVowels(const string& str)

• Description: Counts the number of vowels in the given string.
• Parameters: const string& str – the input string to be processed.
• Returns: int – the number of vowels in the input string.

Function: int main()

• Description: The main function of the program.
• Process:
  • Prompts the user to enter a string.
  • Calls the countVowels function to count the number of vowels.
  • Displays the number of vowels found in the string.
• Returns: int – exit status of the program (0 for successful execution).