What is meant by the term “half open range” and “off the end value” in C++?

May 13, 2015 by Tim Elhajj 1 Comment

These aren’t C++ specific terms, they are general mathmatics terms.

[] and () denote whether the range is inclusive/exclusive of the endpoint:

• [ includes the endpoint
• ( excludes the endpoint
• [] = ‘Closed’, includes both endpoints
• () = ‘Open’, excludes both endpoints
• [) and (] are both ‘half-open’, and include only one endpoint

Most C++ for-loops cover a half-open range (you include the first element: e.g for int i=0;, but exclude the final element: i < foo, not i ≤ foo)

This great answer is courtesy of jam.

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