矢量索引简称

Question

Suppose I have a vector

std::vector<a> A;

I can get access to its member-functions through the . operator and I can index it with the [] operator. If I have a pointer to a vector, eg

std::vector<a> *A;

I can get to its members using the short -> operator, but indexing is very inconvenient, ie (*A)[i] . How can it be written more neatly? Note: I am not satisfied with A->at() , because it does boundary check, which are slow, and for me speed is important.

Answer 1

Bind it to a reference is the easiest way if (*A)[i] is a problem:

std::vector<a>& ref = *A;
ref[i] = 0; //use reference

Normally I'd prefer passing vectors by reference instead of pointer anyway unless you really want to allow NULL values too.