Stack.cpp

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#include <cassert>
#include <iostream>
#include "Stack.h"

using std::cout;

// Constructor
Stack::Stack()
{
}

// Destructor needs to deallocate dynamically allocated nodes:
Stack::~Stack()
{
    // Remove all dynamic nodes from the list:
    Node* iter = head.pnext;
    while ( iter != NULL ) {
        Node* obsolete = iter;
        iter = iter->pnext;
        delete obsolete; // remove node from memory
    }
}

// Push new element to the stack:
void Stack::push( int value )
{
        head.insert( new Node( value ) );
}

// Pop element from the stack:
void Stack::pop()
{
    assert( !empty() );
        Node* obsolete = head.pnext;
        head.remove_next();
    delete obsolete;
}

// Writeable access to element on top of the stack:
int& Stack::top()
{
        return head.pnext->data;
}

// Read-only access to element on top of the stack:
int Stack::top() const
{
        return head.pnext->data;
}

// Return stack size:
size_t Stack::size() const
{
        // minus one accounts for the head node
        return head.size() - 1;
}

// Return true if stack is empty
bool Stack::empty() const
{
        return head.size() == 1;
}

// Print contents of the stack:
void print_stack( Stack const& st )
{
    if ( st.empty() ) {
        cout << "[0] (stack is empty)\n";

    } else {
        print_list( *st.head.pnext );
    }
}

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