#ifndef __STACK_H__
#define __STACK_H__

// This is something briefly discussed in lecture.  We need to say 
// that there's going to be a struct called 'IntStackNode', because the
// IntStack class needs to point to one.  But we don't need to say what
// IntStackNode looks like right now, so we leave it out.  The definition
// of the IntStackNode struct is in stack.cpp.
struct IntStackNode;

class IntStack
{
public:
    // Default constructor that builds an empty IntStack.
    IntStack();

    // Destructor function.  For more information about destructors, see
    // section 7.8 of the textbook.
    ~IntStack();

    // Copy constructor.  Again, see section 7.8.
    IntStack( const IntStack& other );

    // Overloaded assignment operator.  Section 7.8 again.
    IntStack& operator =( const IntStack& other );

    bool isEmpty();           // Is the stack empty?

    void push( int item );    // Push an element onto the stack.
    int pop();                // Pop the top element from the stack.
    int top();                // Get the top element from the stack.

private:
    void delAll();
    void pushAllFrom( IntStackNode *other );

    IntStackNode *ptop;       // A pointer to the top of the stack.
};

#endif // __STACK_H__