Java Program to Count the Total Number of Vowels and Consonants in a String

Given a String count the total number of vowels and consonants in this given string. Assuming String may contain only special characters, or white spaces, or a combination of all. The idea is to iterate the string and checks if that character is present in the reference string or not. If a character is present in the reference increment number of vowels by 1, otherwise, increment the number of consonants by 1.

Example:

Input : String = "GeeksforGeeks"
Output: Number of Vowels = 5
        Number of Consonants = 8

Input : String = "Alice"
Output: Number of Vowels = 3
        Number of Consonants = 2

Approach:

1. Create two variables vow and cons and initialize them with 0.
2. Start string traversing.
3. If i’th character is vowel then increment in vow variable by 1.
4. Else if the character is consonant then increment in cons variable by 1.

Example

Java

// Java Program to Count Total Number of Vowels
// and Consonants in a String

// Importing all utility classes
import java.util.*;

// Main class
class GFG {

     // Method 1
    // To prints number of vowels and consonants
    public static void count(String str)
    {
        // Initially initializing elements with zero
        // as till now we have not traversed
        int vow = 0, con = 0;

        // Declaring a reference String
        // which contains all the vowels
        String ref = "aeiouAEIOU";

        for (int i = 0; i < str.length(); i++) {

            // Check for any special characters present
            // in the given string
            if ((str.charAt(i) >= 'A'
                 && str.charAt(i) <= 'Z')
                || (str.charAt(i) >= 'a'
                    && str.charAt(i) <= 'z')) {
                if (ref.indexOf(str.charAt(i)) != -1)
                    vow++;
                else
                    con++;
            }
        }

        // Print and display number of vowels and consonants
        // on console
        System.out.println("Number of Vowels = " + vow
                           + "\nNumber of Consonants = "
                           + con);
    }

    // Method 2
    // Main driver method
    public static void main(String[] args)
    {
        // Custom string as input
        String str = "#GeeksforGeeks";

        // Calling the method 1
        count(str);
    }
}

Output

Number of Vowels = 5
Number of Consonants = 8

Time Complexity: O(n²) here, n is the length of the string.