Frequently Asked Java Program 30: Java Program to Find Distinct Characters In Given String

Hello Folks,

As part of Frequently Asked Java Programs In Interviews For Freshers And Experienced, in this post we will see a java program to Find Distinct Characters In Given String.

Problem Statement:

User input: Make Selenium Easy

Output: K L N I U Y

Problem Solution: 

Logic:

1. Convert input string in to same case either upper or lower.
2. Replace all whitespace with empty space. 
3. Take first char from given String.
4. lastIndexOf(char c) method of String class gives the index of last occurrence of char in given string. If a character is not repeated in given string,  lastIndexOf should give zero as we took first char to check. If it is zero, print.
5. To repeat step 3 and 4, we must need to replace already checked char from string with empty space.

Java Program:

package StringPrograms;

import java.util.Scanner;

public class FindDistinctCharInString {

        public static void findPrintDistinctCharInString(String inputString) {

                // Converting input string to upper case
                inputString = inputString.toUpperCase();
                
                // Removing all white spaces
                inputString = inputString.replace(" ", "");

                // We need to keep counting char till its length is greater than 0
                while (inputString.length() > 0) {
                        // Extracting first char
                        char c = inputString.charAt(0);
                        /*
                         * lastIndexOf(char c) method of String class gives the index of last occurrence of char in given string. 
                         * If a character is not repeated in given string,  lastIndexOf should give zero as we took first char to check. 
                         * If it is zero, print.
                         */
                        if(inputString.lastIndexOf(c)==0)
                                System.out.print(c+" ");
        
                        // Remove char whose occurrence is checked
                        inputString = inputString.replace(Character.toString(c), "");
                }
                

        }

        public static void main(String[] args) {

                // User input for the string to know distinct characters
                Scanner sc = new Scanner(System.in);
                System.out.println("Please enter the string to find distinct characters:");

                String userInput = sc.nextLine();

                sc.close();

                System.out.println("You entered: " + userInput);

                findPrintDistinctCharInString(userInput);
        }

}

Output:

Please enter the string to find distinct characters:Make Selenium EasyYou entered: Make Selenium Easy

K L N I U Y