Bugs and debugging

New idea

The first bug was a real insect

In 1947, engineers found a real moth stuck inside the Harvard Mark II computer. They taped it into their logbook as the first actual bug ever found. Engineers already called faults "bugs", but that moth made the word famous.

Today a bug is a mistake in a program. The computer does exactly what you wrote, not what you meant, and the gap between the two is the bug. Finding and fixing it is called debugging, and every programmer does it every day.

Some bugs crash the program, and Python prints an error message. Read it from the bottom. The last line names the type of error, like NameError: name 'scroe' is not defined, and just above it Python shows the line number (like line 3) and the line itself. A NameError means Python met a name it has never seen, very often a typo.