stack.h

栈的应用—Polish Calculator

typedef double Stack_entry;
enum Error_code{underflow, overflow, success};

const int maxstack = 10;   //  small value for testing

class MyStack {
public:
   MyStack();
   bool empty() const;
   Error_code pop();
   Error_code top(Stack_entry &item) const;
   Error_code push(const Stack_entry &item);

private:
   int count;
   Stack_entry entry[maxstack];
};