invariants - w3toppers.com

What is an invariant?

An invariant is more “conceptual” than a variable. In general, it’s a property of the program state that is always true. A function or method that ensures that the invariant holds is said to maintain the invariant. For instance, a binary search tree might have the invariant that for every node, the key of the … Read more

What constitutes a valid state for a “moved from” object in C++11?

You define and document for your types what a ‘valid’ state is and what operation can be performed on moved-from objects of your types. Moving an object of a standard library type puts the object into an unspecified state, which can be queried as normal to determine valid operations. 17.6.5.15 Moved-from state of library types … Read more