顺序栈问题(unresolved external symbol)

ArrayStack.h


template<class T>
class ArrayStack
{
        int size;
        int tos;
        T* contain;
    public:
        ArrayStack():size(0),tos(-1),contain(NULL)
        {
        }
        ArrayStack(int MaxSize);
        void Push(T element);
        T Pop();
        bool IsEmpty();
};


ArrayStack.cpp

#include <iostream>
#include <cassert>
#include "ArrayStack.h"
using namespace std;
#define MaxSize 10
//设定顺序栈的最大容量
template<class T>
ArrayStack<T>::ArrayStack(int max=MaxSize)   // 应该这么写！
{
    size = max;
    tos = -1;
    contain = new T[size];
}

//指定元素入栈
template<class T>
void ArrayStack< T >::Push(T element)
{   
    assert(tos != size-1);
    contain[++tos] = element;
}

//栈顶元素出栈
template<class T>
T ArrayStack< T >::Pop()
{
    assert(tos != -1);
    return contain[tos--];
}

//判断顺序栈是否为空
template<class T>
bool ArrayStack< T >::IsEmpty()
{
    return (tos == -1);
}

int main()
{
    ArrayStack<char> small(MaxSize);
    char a;
    do
    {
        cin>>a;
        switch(a)
        {
        case '(':
            small.Push(a);
            break;
        case ')':
            if(!small.IsEmpty())
            {
                small.Pop();
                break;;
            }
            if(small.IsEmpty())
            {
                cout<<"匹配错误!"<<endl;
                exit(0);
                break;
            }
        }
    }while (a != '0');
    if(small.IsEmpty())
    {
        cout<<"匹配正确!"<<endl;
    }
    else
    {
        cout<<"匹配错误!"<<endl;
    }
    return 0;  
}