To find the first non-repeating character from given string,we will put the all character based on their frequency into HashMap and we will check for that character which has only one frequency and that is our character.
Program
import java.util.*;
class FirstNonRepeated {
public static void main(String arg[]) {
System.out.println("Enter String to find First non-repeating
Character");
String s = new Scanner(System.in).nextLine();
fnrc(s);
}
public static void fnrc(String str) {
Character c;
HashMap<Character,Integer> hm = new HashMap<>();
for (int i = 0; i < str.length(); i++) {
c = str.charAt(i);
if (hm.containsKey(c))
hm.put(c, hm.get(c) + 1);
else
hm.put(c, 1);
}
for (int i = 0; i < str.length(); i++) {
c = str.charAt(i);
if (hm.get(c) == 1)
System.out.println(c);
}
}
}
Output
Enter String to find First non-repeating Character
aaaabbbbcddd
c
Press any key to continue . . .
