C++ Forward_list Library - push_front() Function

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Description

The C++ function std::forward_list::push_front() inserts new element at the beginning of forward_list and increases size of forward_list by one.

Declaration

Following is the declaration for std::forward_list::push_front() function form std::forward_list header.

C++11

void push_front (const value_type& val);

Parameters

val − Value of element to be inserted into forward_list.

Return value

None

Exceptions

This member function never throws exception.

Time complexity

Constant i.e. O(1)

Example

The following example shows the usage of std::forward_list::push_front() function.

#include <iostream>
#include <forward_list>

using namespace std;

int main(void) {

   forward_list<int> fl;

   for (int i = 0; i < 5; ++i)
      fl.push_front(i + 1);

   cout << "List contains following elements" << endl;

   for (auto it = fl.begin(); it != fl.end(); ++it)
      cout << *it << endl;

   return 0;
}

Let us compile and run the above program, this will produce the following result −

List contains following elements
5
4
3
2
1