public member function
<stack>

std::stack::stack

explicit stack ( const Container& ctnr = Container() );
Construct stack
Constructs a stack container adaptor object.
A container adaptor keeps a container object as data. This container object is a copy of the argument passed to the constructor, if any, otherwise it is an empty container.

Parameters

ctnr
Container object
Container is the second class template parameter (the type of the underlying container for the stack; by default: deque<T>, see class description).

Example

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
 
// constructing stacks
#include <iostream>
#include <vector>
#include <deque>
#include <stack>
using namespace std;

int main ()
{
  deque<int> mydeque (3,100);     // deque with 3 elements
  vector<int> myvector (2,200);   // vector with 2 elements

  stack<int> first;               // empty stack
  stack<int> second (mydeque);    // stack initialized to copy of deque

  stack<int,vector<int> > third;  // empty stack using vector
  stack<int,vector<int> > fourth (myvector);

  cout << "size of first: " << (int) first.size() << endl;
  cout << "size of second: " << (int) second.size() << endl;
  cout << "size of third: " << (int) third.size() << endl;
  cout << "size of fourth: " << (int) fourth.size() << endl;

  return 0;
}

Output:
size of first: 0
size of second: 3
size of third: 0
size of fourth: 2

Complexity

Constant (one container construction). Although notice that the container construction itself may not take constant time.