Create a function: find index of first non-repeating lowercase letter; return -1 if none.

The NonRepeatingFinder class finds the index of the first non-repeating character in a given string by iterating through each character and checking for duplicates.

class NonRepeatingFinder {
    String inputString;
    int stringLength;

    public NonRepeatingFinder(String inputString) {
        this.inputString = inputString;
        this.stringLength = inputString.length();
    }

    public int findFirstNonRepeatingIndex() {
        int duplicatesCount;
        // Iterate through each character in the string
        for (int currentIndex = 0; currentIndex < stringLength; currentIndex++) {
            duplicatesCount = 0;
            // Compare the current character with all other characters
            for (int otherIndex = 0; otherIndex < stringLength; otherIndex++) {
                // If a duplicate character is found
                if (currentIndex != otherIndex && inputString.charAt(currentIndex) == inputString.charAt(otherIndex)) {
                    duplicatesCount++;
                    break;
                }
            }
            // If no duplicates found for the current character, return its index
            if (duplicatesCount == 0) {
                return currentIndex;
            }
        }
        // Return -1 if no non-repeating character is found
        return -1;
    }
}

The NonRepeatingCharacterFinder class demonstrates the usage of NonRepeatingFinder to identify and print the index of the first non-repeating character in a given string.

public class NonRepeatingCharacterFinder {
    public static void main(String[] args) {
        String givenString = "abcdcaf";
        NonRepeatingFinder finder = new NonRepeatingFinder(givenString);
        int firstNonRepeatingIndex = finder.findFirstNonRepeatingIndex();
        System.out.println(firstNonRepeatingIndex); // Prints the index of the first non-repeating character
    }
}