edd/unidad3/c++/stack/Stack.h

// Project: Stack.cbp
// File   : Stack.h
#ifndef STACK_H
#define STACK_H

#include "Node.h"

template <typename T>
class Stack
{
private:
    int m_count;
    Node<T> * m_top;

public:
    Stack();
    bool IsEmpty();
    T Top();
    void Push(T val);
    void Pop();
};

template <typename T>
Stack<T>::Stack() : m_count(0), m_top(NULL) {}

template <typename T>
bool Stack<T>::IsEmpty()
{
    // return TRUE if there are no items
    // otherwise, return FALSE
    return m_count <= 0;
}

template <typename T>
T Stack<T>::Top()
{
    // Just return the value
    // of m_top node
    return m_top->Value;
}

template <typename T>
void Stack<T>::Push(T val)
{
    // Create a new Node
    Node<T> * node = new Node<T>(val);

    // The Next pointer of this new node
    // will point to current m_top node
    node->Next = m_top;

    // The new Node now becomes the m_top node
    m_top = node;

    // One item is added
    m_count++;
}

template <typename T>
void Stack<T>::Pop()
{
    // Do nothing if Stack is empty
    if(IsEmpty())
        return;

    // Prepare the current m_top
    // to remove
    Node<T> * node = m_top;

    // The new m_top node will be
    // the Next pointer of the current m_top node
    m_top = m_top->Next;

    // Now it's safe to remove
    // the first element
    delete node;

    // One item is removed
    m_count--;
}

#endif // STACK_H