C++ vector push_back

Question

What is the proper way of pushing a new object element onto a std::vector? I want the data to be allocated in the vector. Will this copy the object newrad

Answer 1

In addition to the other answers that verify that the object is copied into the container when using push_back via calls to the copy constructor, you might also keep in mind the new emplace_back functionality added with c++0x.

Calling emplace_back allows you to bypass the creation of any temporary objects and have the object constructed in-place inside the container directly. emplace_back is a varardic template function that accepts the parameters you would pass to the constructor of your object, so in this case:

std::vector<Radio> m_radios;
m_radios.emplace_back(radioNum);

will not create any intermediate temporaries. This can be helpful if your objects are expensive to copy.

Hope this helps.