Find first non repeated character in string in java



In this core java programming tutorial we will write a program to Find first non repeated character in string in java.



Write a program to find out first non-repeating character in string in java.
Example in java>
Given string =this is it
first non-repeating character in string= h

Must read: Reverse words in sentence in java.

Full Program/SourceCode/ Example to Find first non repeated character in string in java>
import java.util.LinkedHashMap;
import java.util.Map;
/** Copyright (c), AnkitMittal www.JavaMadeSoEasy.com */
public class FirstNonRepeatedCharacterInStringExample {
  
   public static void main(String[] args){
      
      String inputString="this is it";
       System.out.println("The first non repeated character in inputString("+inputString+") is :  " + firstNonRepeatedCharacter(inputString));
   }
  
   /**
    * Method returns first non-repeating character in inputString.
    * Returns null if there is no non-repeating character in inputString
    */
   public static Character firstNonRepeatedCharacter(String inputString){
       Map<Character,Integer>  map= new LinkedHashMap<Character ,Integer>(); //LinkedHashMap used so that we could maintain insertion order.
       char ar[]=inputString.toCharArray();
       char ch ;
      
       for (int i=0; i<ar.length; i++){
        ch=ar[i];
       
        if(map.containsKey(ch))   //if map already contains this character as key, get value corresponding to key and increment it.
            map.put(ch, map.get(ch)+1 );
        else        //put character in map with value as 1 (showing first occurrence of key in string)
            map.put(ch, 1) ;
       
       }   
       /*
     * Till this point of program, we have stored all unique characters in map as key & corresponding value representing count of character.
     */  
      
       for (int i=0; i<ar.length; i++ ){
        ch= ar[i];
        if( map.get(ch)  == 1 )   //we have found our first non-repeating character in string.
         return ch;
       }
       return null ;
   }
}
/*OUTPUT
The first non repeated character in inputString(this is it) is :  h
*/


Previous program                                                                  Next program

So in this core java programming tutorial we wrote a program how to Find first non repeated character in string in java.


Having any doubt? or you you liked the tutorial! Please comment in below section.
Please express your love by liking JavaMadeSoEasy.com (JMSE) on facebook, following on google+ or Twitter.



RELATED LINKS>





No comments:

Post a Comment