//#define CLASS_STUDENT //#define CLASS_TIME1 //#define CLASS_TIME2 #define CLASS_TIME3 #ifdef CLASS_TIME3 #include <iostream> using namespace std; class Time { public: void set_time(); void show_time(); private: int hour; int minute; int sec; }; void Time::set_time() { cin>>hour; cin>>minute; cin>>sec; } void Time::show_time() { cout<<hour<<":"<<minute<<":"<<sec<<endl; } int main(int argc, char *argv[]) { Time t1; t1.set_time(); t1.show_time(); Time t2; t2.set_time(); t2.show_time(); system("pause"); return 0; } #elif defined CLASS_TIME2 #include <iostream> using namespace std; class Time { public: int hour; int minute; int sec; }; int main(int argc, char *grgv[]) { void set_time(Time &, int hour=0, int minute=0, int sec=0); //声明函数,指定默认形参,靠右边; void show_time(Time &); //引用做形参 Time t1; set_time(t1, 12, 23, 24); show_time(t1); Time t2; set_time(t2); show_time(t2); //默认参数的调用 system("pause"); return 0; } void set_time(Time &t, int hour, int minute, int sec) { t.hour = hour; t.minute = minute; t.sec = sec; } void show_time(Time &t) { cout<<t.hour<<":"<<t.minute<<":"<<t.sec<<endl; } / #elif defined CLASS_TIME1 #include <iostream> using namespace std; class Time { public: //数据成员公用,暴露不安全。 int hour; int minute; int sec; }; int main(int argc, char *argv[]) { Time t1; cin>>t1.hour; cin>>t1.minute; cin>>t1.sec; cout<<t1.hour<<":"<<t1.minute<<":"<<t1.sec<<endl; system("pause"); return 0; } // #elif defined CLASS_STUDENT #include <iostream> #include "student.h" using namespace std; int main(int argc, char *argv[]) { student stud; stud.display(); system("pause"); return 0; } #endif