CPP/Classes/PureVirtualFunction
From ProgrammingExamples
PureVirtualFunction.cpp
#include <iostream> #include <limits> class Point { public: Point(const double xin, const double yin, const double zin) : x(xin), y(yin), z(zin) {} double x,y,z; virtual void Output() = 0; }; class DerivedClass { void Output() { std::cout << "Point Class." << std::endl; } }; int main(int argc, char *argv[]) { return 0; }
Virtual Functions & Abstract Classes
#include <iostream> class Vehicle { public: /* * Here we declare a Pure Virtual Function * This class has now become an abstract class & * it's instances cannot be created only pointers * */ virtual void SeeMeGo()=0; }; /* Some Derived Classes */ class Car : public Vehicle { public: void SeeMeGo() { std:cout<<"I'm running at 50mph.\n"; } }; class Bike : public Vehicle { public: void SeeMeGo() { std:cout<<"I'm whooshing at 80mph.\n"; } }; class Truck : public Vehicle { public: void SeeMeGo() { std:cout<<"I'm crawling at 20mph.\n"; } }; int main(int argc, char *argv[]) { //Create a Pointer to Abstract Class Vehicle Vehicle *myVehicle; //Create Some Objects Car myCar; Bike myBike; Truck myTruck; //Call Functions myVehicle = &myCar; myVehicle->SeeMeGo(); myVehicle = &myBike; myVehicle->SeeMeGo(); myVehicle = &myTruck; myVehicle->SeeMeGo(); return 1; }