C++ emplace_back: Efficient Vector Element Insertion

emplace_back is a member function of the std::vector container in C++. It is used to insert a new element at the end of the vector, constructed in place with the provided arguments.

Unlike push_back, which copies or moves an existing object into the vector, emplace_back constructs a new object directly in the vector's storage using the provided arguments. This can be more efficient and/or enable certain types of objects that cannot be copied or moved.

Here's an example of using emplace_back to add a new object to a vector:

std::vector<MyObject> myVector;

// Add a new object constructed with arguments 1 and 2
myVector.emplace_back(1, 2);

In this example, MyObject is a user-defined class with a constructor that takes two integer arguments. The emplace_back call constructs a new MyObject with arguments 1 and 2, and adds it to the end of the myVector vector.