Category : iterator

cppreference states in the std::forward_iterator semantic requirements that: Pointers and references obtained from a forward iterator into a range remain valid while the range exists. What exactly does this mean? What if I obtain a pointer from a range’s iterator, then execute some iterator-invalidating action on this range? The iterator might be invalidated and the ..

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I struggle to understand what c++20 ranges add compared to good old fashioned iterators. Yes, I guess there is no need to use begin and end anymore, but simple overloads such as: namespace std { template <typename Container> auto transform(Container&& container, auto&&… args) requires ( requires {container.begin(); container.end(); }) { return transform(container.begin(), container.end(), args…); } ..

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C++20 introduced a std::common_iterator that is capable of representing a non-common range of elements (where the types of the iterator and sentinel differ) as a common range (where they are the same), its synopsis defines as: template<input_­or_­output_­iterator I, sentinel_­for<I> S> requires (!same_­as<I, S> && copyable<I>) class common_iterator { // … private: variant<I, S> v_; // ..

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i would like to make a reusable function that returns an iterator to make it easy to find the middle point of a container and need some help template <typename T> std::vector<int>::const_iterator middlepoint(T it_beg,T it_end){ auto temp = it_beg + it_end / 2; return temp; } the line of code that tries to execute the ..

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New to c++ and I’m having trouble implementing an Iterator class in my LinkedList. I have a Iterator class defined in the private section of my LinkedList class as follows: cs_linked_list.h #ifndef LINKED_LIST_H_ #define LINKED_LIST_H_ #include <initializer_list> #include <iostream> namespace cs { template <typename T> class LinkedList { struct Node; // forward declaration for our ..

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https://stackoverflow.com/a/33307828/9250490 You can find the first 5-sequential-number 12345 via regex_search(s.cbegin(), s.cend()… string s = "abcde, eee12345 11111ddd 55555 hello"; std::smatch m; bool b = std::regex_search(s.cbegin(), s.cend(), m, std::regex("[0-9]{5}")); cout << m[0] << endl; But if I want to find the last 55555, I tried, std::regex_search(s.crbegin(), s.crend(), m, std::regex("[0-9]{5}")); But it doesn’t compile with error, Error ..

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