stack3.cpp

Think in C++ 第二版源码

//: C06:Stack3.cpp {O}
// From Thinking in C++, 2nd Edition
// Available at http://www.BruceEckel.com
// (c) Bruce Eckel 1999
// Copyright notice in Copyright.txt
// Constructors/destructors
#include "Stack3.h"
#include "../require.h"
using namespace std;

Stack::Link::Link(void* dat, Link* nxt) {
  data = dat;
  next = nxt;
}

Stack::Link::~Link() {
  delete data;
}

Stack::Stack() { head = 0; }

void Stack::push(void* dat) {
  head = new Link(dat,head);
}

void* Stack::peek() { return head->data; }

void* Stack::pop() {
  if(head == 0) return 0;
  void* result = head->data;
  Link* oldHead = head;
  head = head->next;
  delete oldHead;
  return result;
}

Stack::~Stack() {
  Link* cursor = head;
  while(head) {
    cursor = cursor->next;
    delete head;
    head = cursor;
  }
  head = 0; // Officially empty
} ///:~