C++언어; 상속(2)

#include <cstring> #include <iostream> using std::cout; using std::endl; class AAA { int a; public: AAA() { cout<<"AAA() call!"<<endl; a=10; } AAA(int i) { cout<<"AAA(int i) call!"<<endl; } }; class BBB:public AAA { int b; public: BBB(){ cout<<"BBB() call!"<<endl; b=20; } BBB(int j) { cout<<"BBB(int j) call!"<<endl; } }; int main() { BBB b; return 0; }

#include <iostream> #include <cstring> using std::endl; using std::cout; class Person { int age; char name[20]; public: int GetAge() const { return age; } const char* GetName() const { return name; } Person(int _age=1, char* _name="noname"){ age=_age; strcpy(name, _name); } }; class Student: public Person { char major[20]; //전공 public: Student(char* _major){ strcpy(major, _major); } const char* GetMajor() const { return major; } void ShowData() const { cout<<"이름: "<<GetName()<<endl; cout<<"나이: "<<GetAge()<<endl; cout<<"전공: "<<GetMajor()<<endl; } }; int main(void) { Student Kim("computer"); Kim.ShowData(); return 0; };

아래의 코드가 작동하지 않는 이유를 고찰하시오.

#include <iostream> #include <cstring> using std::endl; using std::cout; class Person { int age; char name[20]; public: int GetAge() const { return age; } const char* GetName() const { return name; } Person(int _age=1, char* _name="noname"){ age=_age; strcpy(name, _name); } }; class Student: public Person { char major[20]; //전공 public: Student(int _age, char* _name, char* _major){ age=_age; strcpy(name, _name); strcpy(major, _major); } const char* GetMajor() const { return major; } void ShowData() const { cout<<"이름: "<<GetName()<<endl; cout<<"나이: "<<GetAge()<<endl; cout<<"전공: "<<GetMajor()<<endl; } }; int main(void) { Student Kim(20, "Hong Gil Dong", "computer"); Kim.ShowData(); return 0; };

아래의 코드를 잘 이해하시오.

#include <iostream> #include <cstring> using std::endl; using std::cout; class Person { int age; char name[20]; public: int GetAge() const { return age; } const char* GetName() const { return name; } Person(int _age=1, char* _name="noname"){ age=_age; strcpy(name, _name); } }; class Student: public Person { char major[20]; //전공 public: Student(int _age, char* _name, char* _major) : Person(_age, _name) { strcpy(major, _major); } const char* GetMajor() const { return major; } void ShowData() const { cout<<"이름: "<<GetName()<<endl; cout<<"나이: "<<GetAge()<<endl; cout<<"전공: "<<GetMajor()<<endl; } }; int main(void) { Student Kim(20, "Hong Gil Dong", "computer"); Kim.ShowData(); return 0; };

데이터의 Protected를 사용한 이유를 설명하시오.

Protected를 사용할 경우, 상속관계에 있는 경우 접근 가능하다.

#include <iostream> #include <cstring> using std::endl; using std::cout; class Person { /*데이터*/ protected: int age; char name[20]; public: /*자동함수*/ Person(int _age=1, char* _name="noname"){age=_age; strcpy(name, _name);} /*수동함수*/ int GetAge() const {return age;} const char* GetName() const {return name;} }; class Student: public Person { /*데이터*/ char major[20]; public: /*수동함수*/ Student(int _age, char* _name, char* _major):Person(_age, _name) {strcpy(major, _major);} /*수동함수*/ const char* GetMajor() const {return major;} void ShowData() const { cout<<"이름: "<<age<<endl; cout<<"나이: "<<name<<endl; cout<<"전공: "<<major<<endl; } }; int main(void) { Student Kim(20, "Hong Gil Dong", "computer"); Kim.ShowData(); return 0; };