Check my code Please

I've been given an assignment to make 3 template classes for stacks. The 1st is for a static stack. The 2nd for dynamic stacks. The 3rd is for linked lists. The code for the first one is below. I would appreciate someone going over it and seeing if my thinking and code were right. Thank You

#ifndef Main_Savitch_Stack1_H
#define Main_Savitch_Stack1_H
#include <cstdlib>

namespace main_savitch_stack1_H
{
template <class Item>
class stack
{
public:

typedef std::size_t size_type;
typedef Item value_type;
static const size_type CAPACITY = 30;
stack(){used=0;}


void push(const Item& entry);
void pop( );

bool empty( ) const { return (used == 0); }
size_type size( ) const { return used; }
Item top( ) const;

private:
Item data[CAPACITY];
size_type used;
};
}


//IMPLEMENTATION BEGINS HERE

#include <cassert>

template <class Item>
void stack<item>::push(const item& entry)
{
assert (size())<capacity);
data[used]=entry;
++used;
}

template <class Item>
void stack<item>::pop()
{
assert (!empty());
if (!empty())
--used;
}


template <class item>
item stack<item>::top()
{
assert(!empty());
return data[used-1]
}

It was full of syntax errors, but I managed to clear them up. This code at least compiles, but I didn't test to see if the processing is correct or not. The static const member of your class caused my compiler fits despite the correct syntax so I axed it and used a #define macro instead, you can change that as you see fit.

Code:

---

#define CAPACITY 30
namespace Main_Savitch_Stack1_H
{
  template <class Item>
  class stack
  {
  public:   
    stack ( void ) { used=0; }
    void push ( const Item& entry );
    void pop ( void );
    bool empty ( void ) const { return ( used == 0 ); }
    size_t size ( void ) const { return used; }
    Item top ( void );
  private:
    Item data[CAPACITY];
    size_t used;
  };
}

// stack class method fleshy
#include <cassert>
using namespace Main_Savitch_Stack1_H;

template <class Item>
void stack<Item> :: push ( const Item& entry )
{
  assert ( size() ) < capacity );
  data[used] = entry;
  ++used;
}

template <class Item>
void stack<Item> :: pop ( void )
{
  assert ( !empty() );
  if ( !empty() )
    --used;
}

template <class Item>
Item stack<Item> :: top ( void )
{
  assert( !empty() );
  return data[used - 1]
}

---

-Prelude