The STL Algorithms

stack

The stack class supports a stack. Its template specification is shown here:

template <class T, class Container = deque<T> > class stack

Here, T is the type of data being stored and Container is the type of container used to hold the queue. It has the following constructor:

explicit stack(const Container &cnt = Container( ));

The stack( ) constructor creates an empty stack. By default, it uses a deque as a container, but a stack can be accessed only in a last-in, first-out manner. You may also use a vector or list as a container for a stack. The container is held in a protected member called c of type Container.

The following comparison operators are defined for stack:

==, <, <=, !=, >, >=

stack contains the following member functions:

Member	Description
bool empty( ) const;	Returns true if the invoking stack is empty and false otherwise.
void pop( );	Removes the top of the stack, which is technically the last element in the container.
void push(const value_type &val);	Pushes an element onto the end of the stack. The last element in the container represents the top of the stack.
size_type size( ) const;	Returns the number of elements currently in the stack.
value_type &top( ); cont value_type &top( ) const;	Returns a reference to the top of the stack, which is the last element in the container. The element is not removed.