Explain std::vector(tSet.begin(), tSet.end())

Question

In this SO answer there is the following line:

std::vector<int>(tSet.begin(), tSet.end()).swap(tUserNumbers);

Can someone explain the syntax of the portion before .swap? Is there a name to it by which I could look it up?

Answer 1

std::vector<int>(tSet.begin(), tSet.end())
//                          ^ iterator to begin of data range
// tSet.end() is iterator to end of data range

creates a temporary variable which is of type std::vector<int> by copying container named tSet

Is there a name to it by which I could look it up?

Look at this decription of vector constructors:

in particular at constructor (4):

template< class InputIt >
vector( InputIt first, InputIt last, 
        const Allocator& alloc = Allocator() );

which is called sometimes also a range constructor.