《C++ STL开发技术引导》配套光盘 聆听大师级的指点

				#include 
				class B;
				class A{
					int i;
				public:
					A(int i_){i=i_;}
					friend bool operator>(A& a, B& b);
				};
				
				class B{
					double d;
				public:
					B(double d_){d=d_;}
					friend bool operator>(A& a, B& b);
				};
				
				bool operator>(A& a, B& b){
					return a.i > b.d;
				}
				
				int main(void){
					A a(19);
					B b(13.2);
					if(a>b) printf("a>b \n");
					else printf("a					return 0;
				}