Handling Out-of-Range Indices

Question

For a container class, what should the expected behavior be when the user of the class tries to set a value that's outside the class's size?

The method in question is a "replace" method (like operator[]), rather than an "add" method (like operator+=).

I could throw an out_of_range exception or I could just resize the container to accommodate the addition.

Answer 1

An out of range exception is more appropriate here because "replace" semantics normally means that the caller is presuming/asserting there is data at the specified index, which there is not.