void main() {
    char letter = 'x';

    IO.println(letter + 1);
    IO.println((char) (letter + 1));
    IO.println(letter - 'a');
    IO.println((char) ('a' + 2));
    IO.println(letter >= 'a' && letter <= 'z');
}

// From Groundwork, chapter 8 (ch08-strings-as-data), box 16.
// This example is from Groundwork, licensed CC BY-NC-SA 4.0.
// Run with: java ch08_16.java