What is a “tight loop”?

Question

I\'ve heard that phrase a lot. What does it mean?

An example would help.

Answer 1

There's a good example of a tight loop (~ infinite loop) in the video Jon Skeet and Tony the Pony.

The example is:

while(text.IndexOf("  ") != -1) text = text.Replace("  ", " ");

which produces a tight loop because IndexOf ignores a Unicode zero-width character (thus finds two adjacent spaces) but Replace does not ignore them (thus not replacing any adjacent spaces).

There are already good definitions in the other answers, so I don't mention them again.