[C ++ Basics] a small example of passing parameters to the constructor of the parent class in the subclass, including the initialization of constants in the class

// Base class: # include <iostream. h> class Animal () {public: Animal (int height, int weight) {cout <"Animal" <endl;} void eat () {cout <"animal eat" <endl ;}; // subclass: class fish: public Animal () {public: fish (): Animal (400,300 ), a (20) // pass parameters to the constructor of the parent class in the subclass fish. a (20) is the constant a {cout <"fish" <endl;} private: const int a ;}; in the initialization fish class. // description: call the constructor with parameters of the parent class in the subclass. Add a colon (:) after the constructor of the fish class, and then add the constructor with parameters of the parent class. in this way, when the subclass constructor is called, the system will call the constructor with parameters of the parent class to construct the object.