Sentinel while loop for C++

Question

Can anyone tell me what is sentinel while loop in C++? Please give me an example using sentinel while loop.

Answer 1

A "sentinel" in this context is a special value used to indicate the end of a sequence. The most common sentinel is \0 at the end of strings. A "sentinel while loop" would typically have the form:

while (Get(input) != Sentinel) {
  Process(input);
}

Answer 2

A sentinel is a special value, e.g. boolean value, extremely big or small. It is used to determine when to stop the loop.

A good example is in the implementation of merge sort, e.g. read page 4 of http://www.cs.princeton.edu/courses/archive/spr07/cos226/lectures/04MergeQuick.pdf.