#include
using namespace std;
const int SIZE=100;
class stack {
int stck[SIZE];
int tos;
public:
stack(void) {tos=0;}
void push(int i);
int pop(void);
operator int(void) {return tos;}
};
void stack::push(int i){
if(tos==SIZE){
cout << "Stack is full." << endl;
return;
}
stck[tos++] = i;
}
int stack::pop(void){
if(tos==0){
cout << "Stack underrun." << endl;
return 0;
}
return stck[--tos];
}
int main(void){
stack stck;
int i, j;
for(i=0; i<20; i++)
stck.push(i);
j = stck;
cout << j << " items on stack." << endl;
cout << (SIZE - stck) << " spaces open." << endl;
}