public class CharacterCount {

    public static void main(String[] args) {

        String str = "Hello, world!";

        int count = 0;

        // Iterate through each character until null character is encountered

        for (int i = 0; str.charAt(i) != '\0'; i++) {

            count++;

            System.out.println("Character at position " + i + ": " + str.charAt(i));

        }

        System.out.println("Number of characters: " + count);

    }

}