Sequential Stack

#ifndef STRUCT_STACK_H
#define STRUCT_STACK_H

template <class T>
class structstrack{
public:
	virtual void Push(const T&x)=0;
	virtual bool Pop(T&x)=0;
	virtual bool getTop(T&x)const=0;
	virtual bool IsEmpty()const=0;
	virtual bool IsFull()const=0;
	virtual int getSize()const=0;
};
#endif


// StackStruct.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include "StructStack.h"
#include<iostream>
#include<assert.h>
using namespace std;

const int stackIncreament=20;

template <class T>
class SeqStack:public structstrack<T>{
public:
	SeqStack(int sz=50);
	~SeqStack(){delete[]elements;}
	void Push(const T&x);
	bool Pop(T&x);
	bool getTop(T&x)const;
	bool IsEmpty()const{return(top==-1)?true:false;}
	bool IsFull()const{return(top==maxSize-1)?true:false;}
	int getSize()const{return top+1;}
	friend ostream&operator<<<T>(ostream&os,SeqStack<T>&s);
private:
	T *elements;
	int top;
	int maxSize;
	void overflowProcess();
};

template<class T>
SeqStack<T>::SeqStack(int sz):top(-1),maxSize(sz){
	elements=new T[maxSize];
	assert(elements!=NULL);
}

template<class T>
void SeqStack<T>::overflowProcess(){
	T *newArray=new T[maxSize+stackIncreament];
	if(newArray==NULL){
		cerr<<"Allocation spaces error."<<endl;
		exit(1);
	}
	for(int i=0;i<=top;++i)newArray[i]=elements[i];
	maxSize=maxSize+stackIncreament;
	delete[]elements;
	elements=newArray;
}

template<class T>
void SeqStack<T>::Push(const T&x){
	if(IsFull()==true)overflowProcess();
	elements[++top]=x;
}

template<class T>
bool SeqStack<T>::Pop(T&x){
	if(IsEmpty()==true)return false;
	x=elements[top--];
	return true;
}

template<class T>
bool SeqStack<T>::getTop(T&x)const{
	if(IsEmpty()==true)return false;
	x=elements[top];
	return true;
}

template <class T>
ostream&operator<<(ostream&os,SeqStack<T>&s){
	os<<"top="<<s.top<<endl;
	for(int i=0;i<=s.top;++i){
		os<<i<<":"<<s.elements[i]<<endl;
	}
	return os;
}
int _tmain(int argc, _TCHAR* argv[])
{
	SeqStack<int> ss;
	int tmp=0;
	for(int i=0;i<=5;++i){
		cin>>tmp;
		ss.Push(tmp);
	}
	cout<<ss<<endl;
	int tmp2;
	ss.Pop(tmp2);
	ss.Pop(tmp2);
	cout<<ss<<endl;
	system("pause");
	return 0;
}