Java™ Puzzlers: Traps, Pitfalls, and Corner Cases

3. Puzzlers with Character

This chapter contains puzzles that concern strings, characters, and other textual data.

Puzzle 11: The Last Laugh

What does the following program print?

public class LastLaugh {    public static void main(String args[ ] ) {        System.out.print("H" + "a");        System.out.print('H' + 'a');    }}

Solution 11: The Last Laugh

If you are like most people, you thought that the program would print HaHa. It looks as though it concatenates H to a in two ways, but looks can be deceiving. If you ran the program, you found that it prints Ha169. Now why would it do a thing like that?

As expected, the first call to System.out.print prints Ha: Its argument is the expression "H" + "a", which performs the obvious string ...