• Stack is an abstract data structure that contains a collection of elements.
• It implements the Last In First Out (LIFO) mechanism this element is pushed at the end is popped out first.
• It uses an encapsulated object of either deque or vector or list as its underlying container, providing a specific set of member functions to access its elements.
• Stack class is a container adapter and container objects hold data of a similar data type.
• From various sequence containers we can create a stack.
• By default, deque container will be used, if there is no container is provided.
• It cannot be used to manipulate, because container adapters don’t support iterators.
• In stack Type is the Type of element contained and it can be any valid C++ type or even a user-defined type.
• In stack containeris the Type of underlying container object.
• Here three types of member types, they are:
  • Value_type- The first template parameter and donates the element types.
  • Container_type- The second template parameter and denotes the underlying container type.
  • Size_type- It is an unsigned integral type.

Syntax

template <class Type, class Container = deque<Type> > class stack;

Sample Code

#include <iostream>  
#include <stack>  
using namespace std;  
void newstack(stack <int> ss)  
{  
    stack <int> sg = ss;  
    while (!sg.empty())  
    {  
        cout << '\t' << sg.top();  
        sg.pop();  
    }  
    cout << '\n';  
}  
int main ()  
{  
    stack <int> newst;  
    newst.push(55);  
    newst.push(44);  
    newst.push(33);  
    newst.push(22);  
    newst.push(11);  
  
    cout << "The stack newst is : ";  
    newstack(newst);  
    cout << "\n newst.size() : " << newst.size();  
    cout << "\n newst.top() : " << newst.top();  
    cout << "\n newst.pop() : ";  
    newst.pop();  
    newstack(newst);   
    return 0;  
}  

Output