Java Program to Count Number of Vowels in a String
Last Updated :
02 Nov, 2022
In java, the string is a sequence of characters and char is a single digit used to store variables. The char uses 2 bytes in java. In java, BufferedReader and InputStreamReader are used to read the input given by the user from the keyboard. Then readLine() is used for reading a line. The java.io package in java provides input and output through data streams, serialization, and the file system.
We can count the vowels in a string in two ways:
- Iterative
- Recursive
Examples:
Input: GeeksForGeeks
Output: Total no of vowels in string are: 5
Input: ChETaN
Output: Total no of vowels in string are: 2
Method 1: Iterative
Approach:
- We will traverse through the string's characters in a for loop starting from index 0 till size-1.
- And check each character if it is a vowel or not and increment the count variable.
Below is the implementation of the above approach:
Java
// Java Program to Count Number of Vowels
// in a String in a iterative way
import java.io.*;
public class vowel {
public static void main(String[] args)
throws IOException
{
String str = "GeeksForGeeks";
str = str.toLowerCase();
int count = 0;
for (int i = 0; i < str.length(); i++) {
// check if char[i] is vowel
if (str.charAt(i) == 'a' || str.charAt(i) == 'e'
|| str.charAt(i) == 'i'
|| str.charAt(i) == 'o'
|| str.charAt(i) == 'u') {
// count increments if there is vowel in
// char[i]
count++;
}
}
// display total count of vowels in string
System.out.println(
"Total no of vowels in string are: " + count);
}
}
OutputTotal no of vowels in string are: 5
Method 2: Recursive
Approach:
- Check for the base condition if the length of the string is 1, then simply check for that single character if it is a vowel, then return 1 else return 0.
- For dividing the whole string into substrings to return the answer recursively, we will get the answer for the string starting from the first till second last character.
- And finally, return the above answer plus the answer for the check of last character (1 if it is vowel or 0 if it is not)
Below is the implementation of the above approach:
Java
// Java Program to Count Number of Vowels
// in a String in a recursive way
import java.io.*;
class GFG {
// isVowel() function returns 1 if the
// character is a vowel and 0 if it is not
static int isVowel(char chars)
{
if (chars == 'a' || chars == 'e' || chars == 'i'
|| chars == 'o' || chars == 'u') {
return 1;
}
else {
return 0;
}
}
// recursive function to return the number
// of characters in a string
static int vowelno(String str, int l)
{
if (l == 1) {
return isVowel(str.charAt(l - 1));
}
return vowelno(str, l - 1)
+ isVowel(str.charAt(l - 1));
}
public static void main(String[] args)
throws IOException
{
String str = "BufferedOutput";
str = str.toLowerCase();
System.out.println(
"Total number of vowels in string are:");
System.out.println(vowelno(str, str.length()));
}
}
OutputTotal number of vowels in string are:
6
Method 3: Using ArrayList and contains() method
Java
// Java Program to Count Number of Vowels
// in a String
import java.io.*;
import java.util.*;
public class Main{
public static void main(String[] args)throws IOException
{
String str = "GeeksForGeeks";
str = str.toLowerCase();
int count = 0;
String vow ="aeiou";
ArrayList<Character> vowels = new ArrayList<Character>();
for(int i=0;i<vow.length();i++)
{
vowels.add(vow.charAt(i));
}
for (int i = 0; i < str.length(); i++) {
if(vowels.contains(str.charAt(i))){
count++;
}
}
// display total count of vowels in string
System.out.println("Total no of vowels in string are: " + count);
}
}
OutputTotal no of vowels in string are: 5
Similar Reads
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
2 min read
Program to remove consonants from a String Given a string , the task is to remove all the consonants from the string and then print the string. Examples: Input: str= "Welcome to geeksforgeeks" Output: eoe o eeoee Input: str= "What is your name?" Output: a i ou ae? Recommended PracticeRemove consonants from a stringTry It!Approach: Traverse a
6 min read
Java Program to Count the Occurrences of Each Character In Java, counting the occurrences of each character in a string is a fundamental operation that can be done in different ways. This process involves identifying the frequency of each character in the input string and displaying it in a readable format.Example: Input/output to count the occurrences o
5 min read
Java Program to Check Whether the Character is Vowel or Consonant In this article, we are going to learn how to check whether a character is a vowel or a consonant. So, the task is, for any given character, we need to check if it is a vowel or a consonant. As we know, vowels are ‘a’, ‘e’, ‘i’, ‘o’, ‘u’ and all the other characters (i.e. ‘b’, ‘c’, ‘d’, ‘f’ …..) are
4 min read
Java program to count the characters in each word in a given sentence Write a Java program to count the characters in each word in a given sentence? Examples: Input : geeks for geeksOutput :geeks->5for->3geeks->5 Recommended: Please solve it on PRACTICE first, before moving on to the solution. Approach:Here we have to find out number of words in a sentence an
3 min read
How to Validate if a String Starts with a Vowel Using Regex in Java? Regular Expressions in Java allow developers to create patterns for matching strings. In this article, we will learn How to Check whether the Given Character String Starts with a Vowel. Example to Check String is Starting with a VowelInput: "Apple"Output: Is a VowelInput: "Cart"Output: Is not a Vowe
2 min read