Description : Test whether sorted range [first1, last1) contains (includes) all elements from another sorted range [first2, last2).
Example:
std::vector<int> v1 {8, 2, 0, 4};
std::vector<int> v2 {2, 0};
std::vector<int> v3 {1, 0};
// includes requires sorted ranges
std::sort(v1.begin(), v1.end());
std::sort(v2.begin(), v2.end());
std::sort(v3.begin(), v3.end());
auto v1ContainsV2 = std::includes(v1.begin(), v1.end(), // first range
v2.begin(), v2.end()); // second range
// prints 1/true
std::cout << " v1 contains v2? " << v1ContainsV2 << std::endl;
auto v1ContainsV3 = std::includes(v1.begin(), v1.end(), // first range
v3.begin(), v3.end()); // second range
// prints 0/false
std::cout << " v1 contains v3? " << v1ContainsV3 << std::endl;