Non_Repeating_Char.java

class Non_Repeating_Char{

    static final int NO_OF_CHARS = 256;
    static char count[] = new char[NO_OF_CHARS];

    static void getCharCountArray(String str)   {
          for (int i = 0; i < str.length(); i++)
                count[str.charAt(i)]++;
    }
 
    static int firstNonRepeating(String str)    {
        getCharCountArray(str);
        int index = -1, i;
 
        for (i = 0; i < str.length(); i++) {
            if (count[str.charAt(i)] == 1) {
                index = i;
                break;
            }
        } 
        return index;
    }
 
    public static void main(String[] args)   {
       String str = "codewarriors";
        int index = firstNonRepeating(str);
        System.out.println(
            index == -1
                ? "Either all characters are repeating or string "
                      + "is empty"
                : "First non-repeating character is "
                      + str.charAt(index));
    }
}