Question

How to find the first non-repeated character in a string with Java

Answer 1

public class Main {
    static Character getFirstNonRepeatedCharacter(String s) { 
        byte[] count = new byte[256]; 
   
        for (int i = 0; i < s.length(); i++) { 
            count[(int)s.charAt(i)]++ ;
        }
   
        for (int i = 0; i < s.length(); i++) { 
            if (count[(int)s.charAt(i)] == 1)
                return s.charAt(i);
        }
   
        return null;
    } 
    public static void main(String args[]) {
        String s = "java programming"; 
           
        Character ch = getFirstNonRepeatedCharacter(s); 
         
        System.out.print(ch); 
    }
}
   
   
/*
run:
   
j
   
*/

 

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Answer 2

public class Main {
    static Character getFirstNonRepeatedCharacter(String str) { 
        for (char ch :str.toCharArray()) {
            if (str.indexOf(ch) == str.lastIndexOf(ch)) {
                return ch;
            }
        }
   
        return null;
    } 
    public static void main(String args[]) {
        String s = "java programming"; 
           
        Character ch = getFirstNonRepeatedCharacter(s); 
         
        System.out.print(ch); 
    }
}
   
   
/*
run:
   
j
   
*/

 

70+ SQL courses for beginners and professionals