First Half by Iterator Range

Write a function vector<int> firstHalf(const vector<int>& v) that returns a new vector containing the first v.size() / 2 elements of v (integer division, so for an odd size the middle element is left out). Build the result with the range constructor vector<int>(first, last) and iterator arithmetic — do not push elements one by one. For an empty vector return an empty vector.

The test prints the returned vector's elements separated by spaces on one line. For {1, 2, 3, 4} it prints 1 2; for {10, 20, 30, 40, 50} it prints 10 20.

Do NOT write a main function.