Description : Combines elements from sorted ranges [first1, last1) and [first2, last2), to a new range starting at passed argument.
Example:
std::vector<int> v1 {8, 2, 0, 4};
std::vector<int> v2 {7, 3, 5};
// the destination needs to fit all merged values
std::vector<int> destination(v1.size() + v2.size());
// merge requires sorted ranges
std::sort(v1.begin(), v1.end());
std::sort(v2.begin(), v2.end());
std::merge(v1.begin(), v1.end(), // first range
v2.begin(), v2.end(), // second range
destination.begin());
// destination is now {0, 2, 3, 4, 5, 7, 8}
for (auto value : destination) {
std::cout << value << " ";
}