C++ 프로그래밍실습. Visual Studio Smart Computing Laboratory

Transcription

1 C++ 프로그래밍실습 Visual Studio 2015

2 Contents Inheritance Exercise

3 Practice1 Inheritance

4 Practice 1-1 : Inheritance What is inheritance? The heart of OO programming A mechanism to build a new class by deriving the new class from already existing base classes Single inheritance: inherits from one base class Multiple inheritance: inherits from more than two base classes Basic data members and methods for students (e.g., name, student_no, dept, and so on) Student Base class (also called superclass or parent class) Content of a derived class Data members and methods inherited from the base classes Except for constructors and destructors Additional data members and methods specific to the derived class Inherited methods can be overridden GradStudent Additional data members and methods specific to graduate students can be defined (e.g., advisor, degree_course, thesis_title, and so on) Derived class (subclass or child class)

5 Practice 1-1 : Inheritance #include<iostream> #define PI 3.14 using namespace std; class Circle int x; int y; int radius; double get_area() return (PI * radius * radius); ; class Sphere : public Circle int z; double get_volumn() return((4.0 / 3.0) * PI *radius * radius* radius); ;

6 Practice 1-1 : Inheritance int main() Circle c; c.x = 1; c.y = 1; c.radius = 5; Sphere s; s.x = 2; s.y = 2; s.z = 2; s.radius = 2; cout << " 원의면적 : " << c.get_area() << endl; cout << " 구의표면적 : " << s.get_area() << endl; cout << " 구의부피 : " << s.get_volumn() << endl; Execution Result: 원의면적 : 78.5 구의표면적 : 구의부피 :

7 Practice 1-2 : Indirect Inheritance class Animal string species; bool warmblooded;... ; // direct derived class of Animal class Cat : public Animal string range[100]; float favoriteprey[100][100];... ; // direct derived class of Cat // indirect derived class of Animal class HouseCat : public Cat string toys[10000]; string catdoctor; string apparentowner;... ; direct base class for Cat direct base class for HouseCat indirect base class for HouseCat Animal Cat HouseCat directly derived from directly derived from indirectly derived from

8 Practice 1-2 : Indirect Inheritance #include <iostream> using namespace std; class Baseclass1 void basefunc1(); ; void Baseclass1::basefunc1() cout << " 첫번째클래스 " <<endl; class Baseclass2: public Baseclass1 void basefunc2(); ; void Baseclass2::basefunc2() cout << " 두번째클래스 " <<endl;

9 Practice 1-2 : Indirect Inheritance class Baseclass3: public Baseclass2 void basefunc3(); ; void Baseclass3::basefunc3() cout << " 세번째클래스 " << endl; class Derivedclass : public Baseclass3 ; int main () Derivedclass myclass; myclass.basefunc1(); myclass.basefunc2(); myclass.basefunc3(); return 0; Indirectly derived from Baseclass1 Baseclass2 Baseclass3 Derivedclass directly derived from directly derived from directly derived from

10 Practice 1-3 : Protected Members In addition to public and private members, C++ provides protected members Without inheritance, a protected member is just like a private member I.e., only visible within the same class In public inheritance, a protected member of a base class is also protected in its derived classes I.e., also visible in the derived classes Consequently, methods of directly or indirectly derived classes can access protected members from their base classes Note that a friend function of a class can access both private and protected members of the class (refer to chap. 6)

11 Practice 1-3 : Protected Members #include<iostream> #include<string> using namespace std; class Point protected: int x, y; void set(int x, int y) this->x = x; this->y = y; void showpoint() cout << "(" << x << "," << y << ")" << endl; ; class ColorPoint :public Point string color; void setcolor(string color) this->color = color; void showcolorpoint(); ; void ColorPoint::showColorPoint() cout << "color: " << color << endl; showpoint(); int main() Point p; p.set(2, 3); //p.x =5; protected 멤버로선언된 x 접근X //p.y =5; protected 멤버로선언된 y 접근X p.showpoint(); ColorPoint cp; cp.set(3, 4); cp.setcolor("red"); cp.showcolorpoint(); Execution Result: (2,3) color: Red (3,4)

12 Practice 1-4 : Constructors under Inheritance A derived class is a specialized version of a base class Basically, an object of a derived class contains members from the base class It also contains members that are specific to derived class itself Thus, a base class constructor also needs to be invoked when a derived class object is created The base class constructor handles initialization and other matters for the from the base class part of the object And the derived class Plan constructor 9 from handles the added outer by derived space class part of the object initializes [ An object of a derived class ] Parts from the base class Base Class Constructors Parts added by the derived class initializes Derived Class Constructors

13 Practice 1-4 : Constructors under Inheritance #include<iostream> using namespace std; class Base private: int basenum; Base() : basenum(20) cout << "Base()" << endl; Base(int n) : basenum(n) cout << "Base(int n)" << endl; void ShowBaseData() cout << basenum << endl; ; class Derived :public Base private: int derivnum; Derived() : derivnum(30) cout << "Derived()" << endl; Derived(int n) :derivnum(n) cout << "Derived(int n)" << endl; Derived(int n1, int n2) :Base(n1), derivnum(n2) cout << "Derived(int n1, int n2)" << endl; void ShowDerivData() ShowBaseData(); cout << derivnum << endl; ; Plan 9 from outer space

14 Practice 1-4 : Constructors under Inheritance int main() cout << "case1..." << endl; Derived dr1; dr1.showderivdata(); cout << "*********************" << endl; cout << "case2..." << endl; Derived dr2(12); dr2.showderivdata(); cout << "*********************" << endl; cout << "case3..." << endl; Derived dr3(23, 24); dr3.showderivdata(); Plan 9 from outer space Execution Result: case1... Base() Derived() ********************* case2... Base() Derived(int n) ********************** case3... Base(int n) Derived(int n1, int n2) 23 24

15 Practice 1-5 : Constructors &Destructor #include <iostream> using namespace std; class Parent private: int test1; Parent() : test1(1) cout << " 부모생성 " << endl; ~Parent() cout << " 부모소멸 " << endl; ; class Child : public Parent private: int test2; Child() :test2(1) cout << " 자식생성 " << endl; ~Child() cout << " 자식소멸 " << endl; ; int main() Child *myobj = new Child; delete myobj; return 0; Execution Result: 부모생성자식생성자식소멸부모소멸

16 Practice 1-6 Multiple Inheritance With multiple inheritance, a derived class may have two or more base classes With only single inheritances, an inheritance hierarchy forms a tree, with multiple inheritances it may form a graph ( pp.36) Meanings of inheritance In a single inheritance hierarchy, a derived class typically represents a specialized version of its base class In a multiple inheritance hierarchy, a derived class may represents a combination of its multiple base classes BC DC Single inheritance BC1 DC BC2 Multiple inheritance For reference, Java does NOT allow multiple inheritance for classes (c.f., only allows interfaces to inherit from multiple interfaces)

17 Practice 1-6 : Multiple Inheritance #include<iostream> using namespace std; class Adder protected: int add(int a, int b) return a + b; ; class Subtractor protected: int minus(int a, int b) return a - b; ; class Calculator :public Adder, public Subtractor int calc(char op, int a, int b); ; int Calculator::calc(char op, int a, int b) int res = 0; switch (op) case '+': res = add(a, b); break; case '- : res = minus(a, b); break; return res; int main() Calculator cal; cout << "2 + 4 = " << cal.calc('+', 2, 4) << endl; cout << "100-8 = " << cal.calc('-', 100, 8) << endl;

18 Exercise Point 클래스와 Circle 클래스를작성하되 Circle 클래스는 Point 클래스로부터상속받아구현 Point 클래스의멤버변수로좌표 (int x, y) 를포함하고 move, draw 멤버함수를포함. Circle 클래스는멤버변수로중심좌표 (int x, y) 와반지름 (double radius) 을포함하고, 멤버함수로 move, draw, getarea 를포함. * 이때 move 는두클래스모두동일한역할을하며 draw( 좌표출력 ) 는두클래스가서로다른내용으로구현되어야함. * 생성자생성할것. 다음장 main 과결과값참고.

19 Exercise

20 Submit Teaching assistant: 장성수 Office: 신공학관 1216 호 ( 대학원 SCLab 연구실 ) pik1100@naver.com Title of the [2018][Practice#]_student# _ student _ name Ex) [2018][Practice02]_ _ 장성수 Create zip file. (C++ project folder) - 주의 : 메일양식이잘못될경우채점이되지않을수있음. 질문메일 : pik1100@naver.com : 장성수

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