Write a program to find out duplicate characters in a string.

Description:

Write a program to find out duplicate or repeated characters in a string, and calculate the count of repeatation.

Code:

? 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 package com.govindsblog.algos;   import java.util.HashMap; import java.util.Map; import java.util.Set;   public class DuplicateCharsInString {       public void findDuplicateChars(String str){                   Map<Character, Integer> dupMap = new HashMap<Character, Integer>();         char[] chrs = str.toCharArray();         for(Character ch:chrs){             if(dupMap.containsKey(ch)){                 dupMap.put(ch, dupMap.get(ch)+1);             } else {                 dupMap.put(ch, 1);             }         }         Set<Character> keys = dupMap.keySet();         for(Character ch:keys){             if(dupMap.get(ch) > 1){                 System.out.println(ch+"--->"+dupMap.get(ch));             }         }     }           public static void main(String a[]){         DuplicateCharsInString dcs = new DuplicateCharsInString();         dcs.findDuplicateChars("govindsblog");     } }

Output:

g--->2 o--->2