Program to count the number of vowels and consonants in a given string in java - Java Program to Count the Number of Vowels and Consonants in a Sentence

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Program to Count the Number of Vowels and Consonants in a Sentence

Count vowels in a string java: In this article we will see multiple ways to count total number of vowels and consonants in a sentence in Java.

We know English alphabet consists of 26 letters. These alphabets are sub-divided into two parts i.e. Vowels and Consonants.

Vowels:- The letters ‘a’, ‘e’, ‘i’, ‘o’ & ‘u’ are considered as vowels in English
Consonants:- Except vowels, all the remaining letters are considered as consonants in English.

Our task is to count total number of vowels and consonants in English. We will see different approaches to achieve it in Java.

By using For loop
By using User-defined input
By using Recursive methods

Let’s see the approaches one by one.

Method-I :- By using For loop

In this method we will take a FOR loop and iterate through it. Initially we will convert all characters of String to lowercase as we will don’t have to check for A to Z.

Wherever consonant is found we will increment a variable say vow and wherever vowel is found we will increment a variable say cons. Finally cons and vow is printed which gives total number of consonants and vowels respectively.

Approach:

Declare a String variable say str.
Declare and initialize variable say vow, cons to 0.
Store a English sentence in str.
Convert the characters into lower case and store in str.
Take a for loop and iterate till the length of the string.
Inside for loop implement the following.
Declare a variable say temp, with each iteration store a character in temp.
Taking if condition check whether any character equals to a/e/i/o/u. If yes increment vow.
Otherwise if character is a letter and does not satisfy above if condition, increment cons.
After loop execution ends i.e. all characters of the string are checked, print cons and vow.

Program:

public class Main 
{

  public static void main(String[] args) {
    String str = "India is my country.";
    int vow = 0;
    int cons = 0;
    
    // convert the whole string to lowercase
    str = str.toLowerCase();
    // iterate loop till length of the string
    for (int i = 0; i < str.length(); ++i) {
        // store character in temp
      char temp = str.charAt(i);

      // check each character is vowel or not
      if (temp == 'a' || temp == 'e' || temp == 'i' || temp == 'o' || temp == 'u') {
        ++vow;
      }

      // check if there is any character other than vowels
      else if ((temp >= 'a' && temp <= 'z')) {
        ++cons;
      }
      
    }

    System.out.println("Vowels =  " + vow);
    System.out.println("Consonants =  " + cons);
  }
}

Output:

Vowels =  6
Consonants =  10

Method-II :- By using User-defined input

java.util package provide Scanner class which asks user to enter he inputs.

This method is almost similar to Method-I. But we only have to ask the user to enter a input (sentence in this case). Then proceed similarly as approach of Method-I.

Approach

Import Scanner class from java.util package.
Declare and initialize variable say vow, cons to 0.
Make instance of Scanner class.
Declare and String variable say str
Ask user to enter a sentence, that will be stored in str
Convert the characters into lower case and store in str
Take a for loop and iterate till the length of the string.
Inside for loop implement the following.
Declare a variable say temp, with each iteration store a character in temp.
Taking if condition check whether any character equals to a/e/i/o/u. If yes increment vow.
Otherwise if character is a letter and does not satisfy above if condition, increment cons.
After loop execution ends i.e. all characters of the string are checked, print cons and vow.

Program:

import java.util.Scanner;
public class Main
{
   public static void main(String args[])
   {
      int vow = 0, cons=0;
      // Ask user to enter a string
      System.out.println("Please enter a sentence :");
      Scanner sc = new Scanner(System.in);
      // string entered will be stored in str
      String str = sc.nextLine();
      // convert the whole string to lowercase
      str = str.toLowerCase();


      // iterate loop till length of string
      for (int i=0 ; i<str.length(); i++)
      {
         char temp = str.charAt(i);
         // check if character is a vowel
         if(temp == 'a'|| temp == 'e'|| temp == 'i' ||temp == 'o' ||temp == 'u')
         {
            vow ++;
         }
         
         // check if there is any character other than vowels
         else if ((temp >= 'a' && temp <= 'z')) 
         {
         ++cons;
        }

      }
      System.out.println("Vowels =  "+vow);
      System.out.println("Consonants =  "+cons);
   }
}

Output

Please enter a sentence :
India is my country
Vowels =  6
Consonants =  10

Method-III :- By using Recursive methods

In this approach we will recursively check for vowels and count those using recursive methods. Similarly, we will recursively check for consonants and count those using recursive methods.

Approach:

Create a recursive method say checkCons which will convert each character to upper string and checks if the characters are consonant or not.
If yes, it will return to countCons method where it will recursively count the returned characters from checkCons method.
It will iterate a variable say count and after the end of execution of countCons method it will return final value of count to main function.
print the total no. of constants.
For vowels, take a method say checkVowel which checks if character is vowel or not.
If yes, pass it to countVowel where it counts the no of characters returned from countVowel in each recursion.
After no value is returned from checkVowel return the final value to the main method.
Print the total no. of vowels.

Program:

public class Main 
{
 
    // Function to whether the character is a consonant
    static boolean checkCons(char temp)
    {
        // To handle lower case
        temp = Character.toUpperCase(temp);
       // if character is consonant return it
        return !(temp == 'A' || temp == 'E' ||
                temp == 'I' || temp == 'O' ||
                temp == 'U') && temp >= 65 && temp <= 90;
    }
  
    static int countCons(String str)
    {
        int count = 0;
        for (int i = 0; i < str.length(); i++)
      
            // check if the character is consonant by passing it to chekCons
            if (checkCons(str.charAt(i)))
                // if charcater found to be consonant increment count value
                ++count;
        // total no of consonants in the string passed to main method        
        return count;
    }
    
    // method that check if the character is vowel or not
        static int checkVowel(char ch)
    {
        // if character is vowel return 1
        if (ch == 'a' || ch== 'e' || ch== 'i'
            || ch == 'o' || ch== 'u') {
            return 1;
        }
        else {
            return 0;
        }
    }
  
    // recursive function that returns total no of characters in string
    static int countVowel(String str, int n)
    {
        //
        if (n == 1) {
            return checkVowel(str.charAt(n - 1));
        }
        // with each call adds total no of vowel if any found in checkVowel method
        return countVowel(str, n - 1)
            + checkVowel(str.charAt(n - 1));
    }
     
    // Driver code
    public static void main(String args[])
    {
        String str = "India is my country";
        // convert string to lower case and stores in str
        str = str.toLowerCase();
        System.out.println("Consonants = "+ countCons(str));
        System.out.println("Vowels = "+countVowel(str, str.length()));
    }
}

Output:

Consonants = 10
Vowels = 6

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