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// FILE: stack2.h (part of the namespace main_savitch_7B)
// TEMPLATE CLASS PROVIDED: stack<Item> (a stack of items)
// The template parameter, Item, is the data type of the items in the stack,
// also defined as stack<Item>::value_type.
// It may be any of the C++ built-in types (int, char, etc.), or a class
// with a default constructor, a copy constructor, and an assignment
// operator. The definition stack<Item>::size_type is the data type of
// any variable that keeps track of how many items are in a stack.
//
// CONSTRUCTOR for the stack<Item> template class:
// stack( )
// Postcondition: The stack has been initialized as an empty stack.
//
// MODIFICATION MEMBER FUNCTIONS for the stack<Item> class:
// void push(const Item& entry)
// Precondition: size( ) < CAPACITY.
// Postcondition: A new copy of entry has been pushed onto the stack.
//
// Item pop( )
// Precondition: size( ) > 0.
// Postcondition: The top item of the stack has been removed.
//
// CONSTANT MEMBER FUNCTIONS for the stack<Item> class:
// bool empty( ) const
// Postcondition: Return value is true if the stack is empty.
//
// size_type size( ) const
// Postcondition: Return value is the total number of items in the stack.
//
// Item top( )
// Precondition: size( ) > 0.
// Postcondition: The return value is the top item of the stack (but the
// stack is unchanged. This differs slightly from the STL stack (where
// the top function returns a reference to the item on top of the stack).
//
// VALUE SEMANTICS for the stack<Item> class:
// Assignments and the copy constructor may be used with stack<Item>
// objects.
//
// DYNAMIC MEMORY USAGE by the stack<Item> template class:
// If there is insufficient dynamic memory, then the following functions
// throw bad_alloc:
// the copy constructor, push, and the assignment operator.
#ifndef MAIN_SAVITCH_STACK2_H
#define MAIN_SAVITCH_STACK2_H
#include <cstdlib> // Provides NULL and size_t
#include "node2.h" // Node template class from Figure 6.5 on page 308
namespace main_savitch_7B
{
template <class Item>
class stack
{
public:
// TYPEDEFS
typedef std::size_t size_type;
typedef Item value_type;
// CONSTRUCTORS and DESTRUCTOR
stack( ) { top_ptr = NULL; }
stack(const stack& source);
~stack( ) { list_clear(top_ptr); }
// MODIFICATION MEMBER FUNCTIONS
void push(const Item& entry);
void pop( );
void operator =(const stack& source);
// CONSTANT MEMBER FUNCTIONS
size_type size( ) const
{ return main_savitch_6B::list_length(top_ptr); }
bool empty( ) const { return (top_ptr == NULL); }
Item top( ) const;
private:
main_savitch_6B::node<Item> *top_ptr; // Points to top of stack
};
}
#include "stack2.template" // Include the implementation
#endif
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