Container Adaptor
A container adaptor which behaves like a stack (last in, first out).
#include <stack>
template <class T, class Container = deque<T>,
class Allocator = allocator>
class stack ;
The stack container adaptor causes a container to behave like a "last in, first out" (LIFO) stack. The last item that was put ("pushed") onto the stack is the first item removed ("popped" off). The stack can adapt to any container that provides the operations, back(), push_back(), and pop_back(). In particular, deque , list , and vector can be used.
template <class T, class Container = deque<T>,
class Allocator = allocator>
class stack {
public:
// typedefs
typedef typename Container::value_type value_type;
typedef typename Container::size_type size_type;
typedef Allocator allocator_type
// Construct
explicit stack (const Allocator& = Allocator());
allocator_type get_allocator () const;
// Accessors
bool empty () const;
size_type size () const;
value_type& top ();
const value_type& top () const;
void push (const value_type&);
void pop ();
};
// Non-member Operators
template <class T, class Container, class Allocator>
bool operator== (const stack<T, Container, Allocator>&,
const stack<T, Container, Allocator>&);
template <class T, class Container, class Allocator>
bool operator< (const stack<T, Container, Allocator>&,
const stack<T, Container, Allocator>&);
explicit stack (const Allocator& alloc = Allocator());
Constructs an empty stack. The stack will use the allocator alloc for all storage management.
allocator_type get_allocator () const;
Returns a copy of the allocator used by self for storage management.
bool empty () const;
Returns true if the stack is empty, otherwise false.
void pop ();
Removes the item at the top of the stack.
void push (const value_type& x);
Pushes x onto the stack.
size_type size () const;
Returns the number of elements on the stack.
value_type& top ();
Returns a reference to the item at the top of the stack. This will be the last item pushed onto the stack unless pop() has been called since then.
const value_type& top () const;
Returns a constant reference to the item at the top of the stack as a const value_type.
template <class T, class Container, class Allocator>
bool operator== (const stack<T, Container, Allocator>& x,
const stack<T, Container, Allocator>& y);
Equality operator. Returns true if x is the same as y.
template <class T, class Container, class Allocator>
bool operator< (const stack<T, Container, Allocator>& x,
const stack<T, Container, Allocator>& y);
Returns true if the stack defined by the elements contained in x is lexicographically less than the stack defined by the elements of y.
//
// stack.cpp
//
#include <stack>
#include <vector>
#include <deque>
#include <string>
#include <iostream.h>
int main(void)
{
// Make a stack using a vector container
stack<int,vector<int>, allocator> s;
// Push a couple of values on the stack
s.push(1);
s.push(2);
cout << s.top() << endl;
// Now pop them off
s.pop();
cout << s.top() << endl;
s.pop();
// Make a stack of strings using a deque
stack<string,deque<string>, allocator> ss;
// Push a bunch of strings on then pop them off
int i;
for (i = 0; i < 10; i++)
{
ss.push(string(i+1,'a'));
cout << ss.top() << endl;
}
for (i = 0; i < 10; i++)
{
cout << ss.top() << endl;
ss.pop();
}
return 0;
}Output : 2 1 a aa aaa aaaa aaaaa aaaaaa aaaaaaa aaaaaaaa aaaaaaaaa aaaaaaaaaa aaaaaaaaaa aaaaaaaaa aaaaaaaa aaaaaaa aaaaaa aaaaa aaaa aaa aa a
If your compiler does not support template parameter defaults, you are required to supply a template parameter for Container and for Allocator. For example:
You would not be able to write,
stack<int> var;
Instead, you would have to write,
stack<int, deque<int>, allocator> var;
allocator, Containers, deque, list, vector