Challenge: Debug the Broken Program

Kavi's little tea program would not work — the cup came out empty and cold every time. "A program that does the wrong thing has a bug in it," said Kavi, "and a good coder does not panic — a good coder hunts it." Kavi read the steps one line at a time, in order: boil the water … good … put the tea bag in … good … pour cold water on the floor — there! One line was doing the wrong thing. Kavi changed just that line to pour the hot water into the cup, pressed ▶ Run again, and out came a warm cup of tea. "Find the one wrong line, fix it, and run it again to check," Kavi hooted. "That is how you debug."