C++语言程序设计题典

				#include 
				class Sample
				{
				protected:
					int x;
				public:
					Sample() { x=0; }
					Sample(int val) { x=val; }
					void operator++() { x++; }
				};
				class Derived:public Sample
				{
					int y;
				public:
					Derived():Sample() { y=0; }
					Derived(int val1,int val2):Sample(val1) { y=val2; }
					void operator--() { x--;y--; }
					void disp()
					{
						cout 					}
				};
				void main()
				{
					Derived d(3,5);
					d.disp();
					d++;
					d.disp();
					d--;
					d--;
					d.disp();
				}