C++でチェーンスタックのインスタンスコードを実現

3285 ワード

チェーンスタックをカスタマイズし、c++言語で実現し、不足点を指摘してください.
 
  
// MyStack.cpp : 。
// , push( ),pop( ),top( ),size( ),empty( )
#include "stdafx.h"
#include
using namespace std;
//
template
struct NODE
{
 NODE* next;
 T data;
};
template
class MyStack
{
public:
 MyStack()
 {
  phead = new NODE;
  if (phead == NULL)
  {
   cout << "Failed to malloc a new node. " << endl;
  }
  else
  {
   phead->data = NULL;
   phead->next = NULL;
  }
 }

 //
 void push(T e)
 {
  NODE* p = new NODE;
  if (p == NULL)
  {
   cout << "Failed to malloc a new node. " << endl;
  }
  else
  {
   p->data = e;
   p->next = phead->next;
   phead->next = p;
  }
 }

 //
 T pop()
 {
  T e;
  NODE* p = phead->next;
  if(p != NULL)
  {
   phead->next = p->next;
   e = p->data;
   delete p;
   return e;
  }
  else
  {
   cout << "There is no elements in the stack." << endl;
   return NULL;
  }
 }

 //
 T top()
 {
  T e;
  NODE* p = phead->next;
  if (p != NULL)
  {
   e = p->data;
   return e;
  }
  else
  {
   cout << "There is no elements in the stack." << endl;
   return NULL;
  }
 }
 //
 int size()
 {
  int count(0);
  NODE* p = phead->next;
  while (p != NULL)
  {
   p = p->next;
   count++;
  }
  return count;
 }
 // stack
 bool empty()
 {
  NODE* p = phead;
  if (p->next == NULL)
  {
   return true;
  }
  else
  {
   return false;
  }
 }
private:
 NODE* phead;
};
int _tmain(int argc, _TCHAR* argv[])
{
 MyStack sta;
 sta.push(1);
 sta.push(2);
 sta.push(3);
 cout << "The size of the stack now is " << sta.size() << endl;
 sta.pop();
 cout << "The top element is " << sta.top() << endl;
 cout << "The size of the stack now is" << sta.size() << endl;
 if (sta.empty())
 {
  cout << "This stack is empty." << endl;
 }
 else
 {
  cout << "This stack is not empty." << endl;
 }
 return 0;
}