Write a java program to Remove duplicate characters in a given String ?

Write a java program to Remove duplicate characters in a given String ?

import java.util.LinkedHashSet;

import java.util.Scanner;

import java.util.Set;

public class RemoveDuplicateCharacters {

      public String removeDuplicates(String input) {

            Set<Character> set = new LinkedHashSet<>();

            for (int i = 0; i < input.length(); i++) {

                  set.add(input.charAt(i));

            }

            StringBuilder sb = new StringBuilder();

            for (Character c : set) {

                  sb.append(c);

            }

            return sb.toString();

      }

      public static void main(String[] args) {

            RemoveDuplicateCharacters rd = new RemoveDuplicateCharacters();

            Scanner scanner = new Scanner(System.in);

            System.out.println("Please enter a String:");

            String input = scanner.next();

            System.out.println("RESULT IS : "+rd.removeDuplicates(input));

      }

}

Ouput:

Please enter a String:

mmmaaadddhhhuuu

RESULT IS : madhu 

Write a Java Program Without using reverse function?

Write a Java Program Without using reverse Funtion?

import java.util.Scanner;

public class ReverseStringWithoutReverseFunction {

       public static String reverse(String str) {

              StringBuilder sb = new StringBuilder();

              char[] string = str.toCharArray();

              for (int i = string.length - 1; i >= 0; i--) {

                     sb.append(string[i]);

              }

              System.out.println(sb.toString());

              return sb.toString();

       }

       public static void main(String[] args) {

              Scanner keyboard = new Scanner(System.in);

              System.out.println("Enter a String:");

              String input = keyboard.next();

              reverse(input);

       }

}