Request for member which is not is of non class

I have scoured this site and others and couldn't find any help with this. I have no idea where I am going wrong.

I am trying to test if a stack is empty (or full in some cases). For some reason, I keep getting this error. I played around with code but it didn't help, it only gave rise to more bugs. Please take a look at the code and tell me where I have gone wrong. Thanks!

#include<iostream>
#include <cstdlib>
#include <string>
#include <stdexcept>

using namespace std;

template <class TYPE> class Stack {
template<class T> //<----note this: i.e make it template!
friend ostream& operator << (ostream &, const Stack<TYPE> &);

private: 
int size; //size of stack
int stackMax; //stack capacity
TYPE *aStack; //an array for entries in the stack

public: 
    Stack(){ 

        size = 0;
        stackMax = 32;
        aStack = new TYPE [stackMax];

    }//constructor

    ~Stack(){ 
    }//destructor

    //This function tests if a stack is empty.
    bool empty(){ 

        if(size == 0){
            return true;
        }

        return false;

    }//end empty function

    //This function tests if a stack is full

    bool full(){ 

        if(size == stackMax){
             return true;
        }

        return false;

     }//end full function

     //This function removes the top entry off aStack.
     void pop(){ 

        if (aStack.empty()){
            cout <<"Error: stack empty\n";  
        }else{
            size--;   
        }

     }//end pop function

     //This function pushes an entry onto aStack.
     void push(TYPE entry) { 

        if(!aStack.full()){
           aStack[size++] = entry;
        }else{
         cout<< "Error: stack full\n";
        }

     }//end push function

     //this function returns the current top entry
     TYPE top(){ 
        if(aStack.empty()){

           cout <<"Error: stack empty\n";

        }
       return aStack[size-1];  

      }//end top function


  };//end Stack class

template<class TYPE> //<----note this: i.e make it template!        
ostream& operator<<(ostream &out, const Stack<TYPE> &aStack){
int size = aStack.size();
out << "stack: ";
    if(size == 0)
                out << "empty";
    else{
                out << aStack[size];
                for (size ; size = 0 ; size--){
        out << "\n" << aStack[size];
                }
    }
        return out;
}//end ostream function

int main() { 
    Stack<int>    intStack;  // stack of ints 
    Stack<string> stringStack;    // stack of strings 

    // manipulate int stack 
intStack.push(2); 
intStack.push(3); 
intStack.push(4); 
intStack.push(5); 
intStack.push(6); 
intStack.push(7); 
intStack.top();
intStack.pop();
cout << intStack;

    // manipulate string stack 
    stringStack.push ("hello"); 
    stringStack.pop(); 

}