C++ Stack Data Structure

#include <iostream>
using namespace std;
class Stack//from  w ww . jav  a2  s.  c  o  m
{
   private:
       enum { MAX = 10 };        //(non-standard syntax)
       int st[MAX];              //stack: array of integers
       int top;                  //number of top of stack
   public:
       Stack()                   //constructor
       { top = 0; }
       void push(int var)        //put number on stack
       { st[++top] = var; }
       int pop()                 //take number off stack
       { return st[top--]; }
};
int main()
{
   Stack s1;
   s1.push(11);
   s1.push(22);
   cout << "1: " << s1.pop() << endl;  //22
   cout << "2: " << s1.pop() << endl;  //11
   s1.push(33);
   s1.push(44);
   s1.push(55);
   s1.push(66);
   cout << "3: " << s1.pop() << endl;  //66
   cout << "4: " << s1.pop() << endl;  //55
   cout << "5: " << s1.pop() << endl;  //44
   cout << "6: " << s1.pop() << endl;  //33
   return 0;
}