The function template std::bind generate a forwarding call wrapper of origin function, it returns a function object.
We can just call the wrapper to invoke the origin function.
The class template std::function is function wrapper, the instance of it can be copied and store.
We often need to delete some elements in an STL set. But it causes a strange bug if we are careless sometimes. One newbie in C Plus Plus program language may write the following code to delete all odd numbers in a set. int main() { vector<int> vec{ 1, 3, Read more…
Driven class of unary_function can be used to check a single element based on special condition.Programmer can regard it as some algorithms’ parameter, such as count_if, find_if, and find_if_not.The following code shows how to write a customized unray class and use it. C++ struct Widget { int GetSpeed() const { return speed; } Widget( const Read more…
We need not sort all elements sometimes. Here are a few simple examples of STL algorithms partial_sort, nth_element, and partition. partial_sort For example, find the 5 biggest ones in 10 random numbers. #include <iostream> #include <vector> #include <cstdlib> #include <ctime> #include <algorithm> using namespace std; int main() { vector<int> values; Read more…
We need a flexible compare way for our objects in some situations, so it’s necessary to write our own compare class. The article has an example which puts all widgets in a multiset container, the widgets should be sort by its data member Speed. The widgets are created with random Read more…
count STL algorithm count can help us to count the elements that are equal to value.Its syntax is like the following form: C++ template typename iterator_traits::difference_type count( InputIt first, InputIt last, const T &value ); Example: C++ #include #include #include using namespace std; int main(int argc, char *argv[]) { vector Read more…
STL Algorithm std::lexicographical_compare is an algorithm which can be used to compare string lexicographically.We can give our comparing function to make it work without pay attention to capital and small letter. C++ template constexpr bool lexicographical_compare( InputIt1 first1, InputIt1 last1, InputIt2 first2, InputIt2 last2, Compare comp ); Example: C++ #include Read more…
std::unique_copy is an algorithm which can be used to copy elements without duplicating objects in adjacent locations. template< class InputIt, class OutputIt > OutputIt uniquecopy( InputIt first, InputIt last, OutputIt dfirst ); Usage example: C++ #include #include #include #include int main() { std::string s1 = “This is a story about Read more…