forward_list emplace_after() and emplace_front() in C++ STL Last Updated : 31 Jul, 2018 Improve Improve Like Article Like Save Share Report The forward_list::emplace_after() is a builtin function in C++ STL which is used to insert a new element after the element at position specified in the argument. This insertion of the new element increases the size of the container by one. Syntax: forward_list_name.emplace_after(iterator position, elements) Parameters: The function accepts two mandatory parameter which are described below: position: it specifies the iterator which points to the position in the container after which new element is to be inserted. element: specifies the new element to be inserted after the position. Return Value :This function returns an iterator that points to the newly inserted element. Below program illustrates the above mentioned function: // C++ program to illustrate the // forward_list::emplace_after() function #include <forward_list> #include <iostream> using namespace std; int main() { forward_list<int> fwlist = { 1, 2, 3, 4, 5 }; auto it_new = fwlist.before_begin(); // use of emplace_after function // inserts elements at positions it_new = fwlist.emplace_after(it_new, 8); it_new = fwlist.emplace_after(it_new, 10); // cout << "The elements are: " for (auto it = fwlist.cbegin(); it != fwlist.cend(); it++) { cout << *it << " "; } return 0; } Output: The elements are: 8 10 1 2 3 4 5 The forward_list::emplace_front() is a built-in function in C++ which is used to insert a new element at the beginning of the forward_list just before the first element. This increases the size of container by one. Syntax: forward_list_name.emplace_front(elements) Parameters: The function accepts one mandatory parameter element which is to be inserted at the start of the container. Return Value: It returns nothing. Below program illustrates the above function. // C++ program to illustrate the // forward_list::emplace_front() function #include <forward_list> #include <iostream> using namespace std; int main() { forward_list<int> fwlist = { 1, 2, 3, 4, 5 }; // use of emplace_front function // inserts elements at front fwlist.emplace_front(8); fwlist.emplace_front(10); cout << "Elements are: "; // Auto iterator for (auto it = fwlist.cbegin(); it != fwlist.cend(); it++) { cout << *it << " "; } return 0; } Output: Elements are: 10 8 1 2 3 4 5 Like Article Suggest improvement Previous forward_list::cend() in C++ STL with Example Next forward_list resize() function in C++ STL Share your thoughts in the comments Add Your Comment Please Login to comment...