Java Program to Count Alphabets Digits and Special Characters in a String

Write a Java Program to Count Alphabets Digits and Special Characters in a String with an example. In this Java count digits, alphabets, and special characters in a string example, we first used for loop to iterate aldisp_str. Inside the loop, to keep the code simple, we assigned (ch = aldisp_str.charAt(i)) each character to ch. Next, we used the Else If statement. 

Within the first if condition (ch >= ‘a’ && ch <= ‘z’ || ch >= ‘A’ && ch <= ‘Z’ ), we check whether the character is an alphabet. If true, we increment the alph value. In the else if statement, we used (ch >= ‘0’ && ch <= ‘9’) to check whether the character is a digit, and if true, increment the digit value. Else, increment the special character value.

import java.util.Scanner;

public class CountAlpDigiSpl1 {
	private static Scanner sc;
	public static void main(String[] args) {
		String aldisp_str;
		int i, alph, digi, spl;
		alph = digi = spl = 0;
		char ch;
		
		sc= new Scanner(System.in);
		System.out.print("\nPlease Enter Alpha Numeric Special String =  ");
		aldisp_str = sc.nextLine();
		
		for(i = 0; i < aldisp_str.length(); i++)
		{
			ch = aldisp_str.charAt(i);
			if(ch >= 'a' && ch <= 'z' || ch >= 'A' && ch <= 'Z' ) {
				alph++;
			}
			else if(ch >= '0' && ch <= '9') {
				digi++;
			}
			else {
				spl++;
			}
		}		
		System.out.println("\nNumber of Alphabet Characters  =  " + alph);
		System.out.println("Number of Digit Characters     =  " + digi);
		System.out.println("Number of Special Characters   =  " + spl);
	}
}

Java Program to Count Alphabets Digits and Special Characters in a String using While loop

import java.util.Scanner;

public class CountAlpDigiSpl2 {
	private static Scanner sc;
	public static void main(String[] args) {
		String aldisp_str;
		int i, alph, digi, spl;
		i = alph = digi = spl = 0;
		char ch;
		
		sc= new Scanner(System.in);

		System.out.print("\nPlease Enter Alpha Numeric Special String =  ");
		aldisp_str = sc.nextLine();
		
		while(i < aldisp_str.length())
		{
			ch = aldisp_str.charAt(i);
			if(ch >= 'a' && ch <= 'z' || ch >= 'A' && ch <= 'Z' ) {
				alph++;
			}
			else if(ch >= '0' && ch <= '9') {
				digi++;
			}
			else {
				spl++;
			}
			i++;
		}		
		System.out.println("\nNumber of Alphabet Characters  =  " + alph);
		System.out.println("Number of Digit Characters     =  " + digi);
		System.out.println("Number of Special Characters   =  " + spl);
	}
}

Please Enter Alpha Numeric Special String =  9In12&*belo 33j^%&*(?hi

Number of Alphabet Characters  =  9
Number of Digit Characters     =  5
Number of Special Characters   =  9

In this Java count digits, alphabets, and special characters in a string example, we compare the ASCII values instead of comparing characters.

import java.util.Scanner;

public class CountAlpDigiSpl3 {
	private static Scanner sc;
	public static void main(String[] args) {
		String aldisp_str;
		int i, alph, digi, spl;
		i = alph = digi = spl = 0;
		int asci;
		
		sc= new Scanner(System.in);

		System.out.print("\nPlease Enter Alpha Numeric Special String =  ");
		aldisp_str = sc.nextLine();
		
		for(i = 0; i < aldisp_str.length(); i++)
		{
			asci = aldisp_str.codePointAt(i);
			if(asci >= 48 && asci <= 57 ) {
				digi++;
			}
			else if(asci >= 65 && asci <= 90 || asci >= 97 && asci <= 122)  {
				alph++;
			}
			else {
				spl++;
			}
		}		
		System.out.println("\nNumber of Alphabet Characters  =  " + alph);
		System.out.println("Number of Digit Characters     =  " + digi);
		System.out.println("Number of Special Characters   =  " + spl);
	}
}

Please Enter Alpha Numeric Special String =  Ja@#va2020!world2.0

Number of Alphabet Characters  =  9
Number of Digit Characters     =  6
Number of Special Characters   =  4

In Java, we have a built-in function isdigit (Character.isDigit(ch) to check the character is a digit or not. isAlphabetic function (Character.isAlphabetic(ch)) to check the character is a alphabet. If both those conditions are false, then the character is special.

import java.util.Scanner;

public class CountAlpDigiSpl4 {
	private static Scanner sc;
	public static void main(String[] args) {
		String aldisp_str;
		int i, alph, digi, spl;
		alph = digi = spl = 0;
		char ch;
		
		sc= new Scanner(System.in);

		System.out.print("\nPlease Enter Alpha Numeric Special String =  ");
		aldisp_str = sc.nextLine();
		
		for(i = 0; i < aldisp_str.length(); i++)
		{
			ch = aldisp_str.charAt(i);
			if(Character.isDigit(ch)) {
				digi++;
			}
			else if(Character.isAlphabetic(ch))  {
				alph++;
			}
			else {
				spl++;
			}
		}		
		System.out.println("\nNumber of Alphabet Characters  =  " + alph);
		System.out.println("Number of Digit Characters     =  " + digi);
		System.out.println("Number of Special Characters   =  " + spl);
	}
}

Please Enter Alpha Numeric Special String =  !@34*(Monday0?

Number of Alphabet Characters  =  6
Number of Digit Characters     =  3
Number of Special Characters   =  5

This Java code to Count Alphabets Digits and Special Characters in a String is the same as the above. Here, we separated the Alphabets, Digits, and special character’s logic using Java functions.

import java.util.Scanner;

public class CountAlpDigiSpl5 {
	private static Scanner sc;
	public static void main(String[] args) {
		String aldisp_str;
		
		sc= new Scanner(System.in);

		System.out.print("\nPlease Enter Alpha Numeric Special String =  ");
		aldisp_str = sc.nextLine();
		
		CountDigitsAlphabetsSpecials(aldisp_str);
	}
	public static void CountDigitsAlphabetsSpecials(String aldisp_str) {
		char ch;
		int alph, digi, spl;
		alph = digi = spl = 0;
		
		for(int i = 0; i < aldisp_str.length(); i++)
		{
			ch = aldisp_str.charAt(i);
			if(Character.isDigit(ch)) {
				digi++;
			}
			else if(Character.isAlphabetic(ch))  {
				alph++;
			}
			else {
				spl++;
			}
		}		
		System.out.println("\nNumber of Alphabet Characters  =  " + alph);
		System.out.println("Number of Digit Characters     =  " + digi);
		System.out.println("Number of Special Characters   =  " + spl);
	}
}

Please Enter Alpha Numeric Special String =  Sep14<>?temb@r

Number of Alphabet Characters  =  8
Number of Digit Characters     =  2
Number of Special Characters   =  4