Count Number Of Vowels In A String - Java | AskTheCode

How to count total no. of vowels in a String | Java Programming | AskTheCode

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Problem:

Java program to count how many vowels have been used in a user given String.

There can be several ways to count the number of vowels in a String. Here, we've published

5 different ways to count the number of vowels in a String in Java. The three approaches are normal String iterative methods, that count the vowel during iteration. The rest two approaches are recursion-based.

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Input Sample:

Hello Coders, Welcome to AskTheCode.

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Output Sample:

12

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Code:

Method 1:

import java.util.Scanner;

class VowelsInString{
	public static void main(String[] args) {
		try{
			System.out.print("Enter a string: ");
			String str = read();
			write("The string is "+str+"\n");
			write("Total vowels found: "+countVowels(str)+"\n");
		} catch (Exception e){
			System.out.print(e+" raised!\n");
		};
	}
	private static int countVowels(String s){
		int count = 0;
		for (char c : s.toCharArray()){
			if ((c == 65) || (c == 97) || (c == 69) || (c == 101) || (c == 73) || (c == 105) || (c == 79) || (c == 111) || (c == 85) || (c == 117))
				count++;
		}
		return count;
	}
	protected static String read() throws java.lang.Exception{
		Scanner sc=new Scanner(System.in);
		return sc.nextLine();
	}
	protected static void write(String s){
		System.out.print(s);
	}
}

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Method 2:

import java.util.Scanner;

class VowelsInString{
	public static void main(String[] args) {
		try{
			System.out.print("Enter a string: ");
			String str = read();
			write("The string is "+str+"\n");
			write("Total vowels found: "+countVowels(str)+"\n");
		} catch (Exception e){
			System.out.print(e+" raised!\n");
		};
	}
	private static int countVowels(String s){
		int count = 0;
		for (char c : s.toCharArray()){
			if ((c == 'A') || (c == 'a') || (c == 'E') || (c == 'e') || (c == 'I') || (c == 'i') || (c == 'O') || (c == 'o') || (c == 'U') || (c == 'u'))
				count++;
		}
		return count;
	}
	protected static String read() throws java.lang.Exception{
		Scanner sc=new Scanner(System.in);
		return sc.nextLine();
	}
	protected static void write(String s){
		System.out.print(s);
	}

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Method 3:

import java.util.Scanner;

class VowelsInString{
	public static void main(String[] args) {
		try{
			System.out.print("Enter a string: ");
			String str = read();
			write("The string is "+str+"\n");
			write("Total vowels found: "+countVowels(str)+"\n");
		} catch (Exception e){
			System.out.print(e+" raised!\n");
		};
	}
	private static int countVowels(String s){
		int count = 0;
		for (int i=0; i<s.length(); i++){
			if ((s.charAt(i) == 'A') || (s.charAt(i) == 'a') || (s.charAt(i) == 'E') || (s.charAt(i) == 'e') || (s.charAt(i) == 'I') || (s.charAt(i) == 'i') || (s.charAt(i) == 'O') || (s.charAt(i) == 'o') || (s.charAt(i) == 'U') || (s.charAt(i) == 'u'))
				count++;
		}
		return count;
	}
	protected static String read() throws java.lang.Exception{
		Scanner sc=new Scanner(System.in);
		return sc.nextLine();
	}
	protected static void write(String s){
		System.out.print(s);
	}
}

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Method 4:

import java.util.Scanner;

class VowelsInString{
	public static void main(String[] args) {
		try{
			System.out.print("Enter a string: ");
			String str = read();
			write("The string is "+str+"\n");
			write("Total vowels found: "+countVowels(str, 0)+"\n");
		} catch (Exception e){
			System.out.print(e+" raised!\n");
		};
	}
	private static int countVowels(String s, int index){
		if (index >= s.length())
			return 0;

		int count = (s.charAt(index) == 'A') || (s.charAt(index) == 'a') || (s.charAt(index) == 'E') || (s.charAt(index) == 'e') || (s.charAt(index) == 'I') || (s.charAt(index) == 'i') || (s.charAt(index) == 'O') || (s.charAt(index) == 'o') || (s.charAt(index) == 'U') || (s.charAt(index) == 'u') ? 1 : 0;
		return count + countVowels(s, index+1);
	}
	protected static String read() throws java.lang.Exception{
		Scanner sc=new Scanner(System.in);
		return sc.nextLine();
	}
	protected static void write(String s){
		System.out.print(s);
	}
}

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Method 5:

import java.util.Scanner;

class VowelsInString{
	public static void main(String[] args) {
		try{
			System.out.print("Enter a string: ");
			String str = read();
			write("The string is "+str+"\n");
			write("Total vowels found: "+countVowels(str.toCharArray(), 0)+"\n");
		} catch (Exception e){
			System.out.print(e+" raised!\n");
		};
	}
	private static int countVowels(char[] charArr, int i){
		if (i >= charArr.length)
			return 0;

		char c = charArr[i];
		int count = ((c == 65) || (c == 97) || (c == 69) || (c == 101) || (c == 73) || (c == 105) || (c == 79) || (c == 111) || (c == 85) || (c == 117)) ? 1 : 0;
		return count + countVowels(charArr, ++i);
	}
	protected static String read() throws java.lang.Exception{
		Scanner sc=new Scanner(System.in);
		return sc.nextLine();
	}
	protected static void write(String s){
		System.out.print(s);
	}
}

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Note: There can be several other ways apart from the ways showed above.

If you can try much more ways than this, then, that's appreciable.