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
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
*/
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