C++ 상속

# 상속 override

#include <stdio.h>
#include <string.h>

class Human
{
protected:
    char name[20];
    int age;
public:
    Human(const char *aname, int aage)
    {
        strcpy(name, aname);
        age=aage;
    }
    void intro()
    {
        printf("이름=%s, 나이=%d\n",name,age);
    }
};

class Student : public Human
{
protected:
    int stunum;
public:
    Student(const char *aname, int aage, int astunum) : Human(aname,aage)
    {
        stunum = astunum;
    }
    void study()
    {
        printf("2*2=4, 3*2=6\n");
    }
    void intro()
    {
        printf("%d학번은 %s입니다.\n",stunum,name);
    }
};

class Graduate : public Student
{
protected:
    char thesis[32];
public:
    Graduate(const char *aname, int aage, int astunum, const char *athesis):Student(aname,aage,astunum)
    {
        strcpy(thesis, athesis);
    }
    void research()
    {
        printf("%s을 연구하고 논문을 슨다.\n",thesis);
    }
};

int main()
{
    
    Human kim("김퐁핑",30);
    kim.intro();
    Student han("한붕붕",22,12345);
    han.intro();
    
   Graduate moon("문퐁퐁",23,9333,"게임방상권분석");
   moon.research();
}

 

# 다중상속

#include <stdio.h>

class A
{
protected:
    int a;
public:
    A(int aa) {a=aa;}
};

//2중 상속을 피하기 위해 A를 가상기반 클래스로 지정한다.
//가상기반 클래스로 지정하지 않으면 D의 a가 B::a인지, C::a인지
//헷갈리고, 실수할 수 있으므로 주의할 것!
class B : virtual public A
{
protected:
    int b;
public:
    B(int aa, int ab) : A(aa) {b=ab;}
};

class C : virtual public A
{
protected:
    int c;
public:
    C(int aa,int ac) : A(aa) {c=ac;}
};

class D : public B, public C
{
protected:
    int d;
public:
    D(int aa,int ab,int ac,int ad) : A(aa), B(aa,ab), C(aa,ac) {d=ad;}
    void fD()
    {
        b=1;
        c=2;
        a=3;
    }
};

int main()
{
    D d(1,2,3,4);
}

 

# 포함과 private 상속(구현상속)

  ( // 포함 코드 )

#include <stdio.h>
#include <string.h>

class Date
{
protected:
    int year, month, day;
public:
    Date(int y, int m, int d)
    {
        year = y;
        month = m;
        day = d;
    }
    void outDate()
    {
        printf("%d,%d,%d",year,month,day);
    }
};

class Product : private Date
{
private:
    char name[64];
    char company[32];
    int price;
    //Date validto; 디폴트 생성자로 validto객체를 만듬
public:
    Product(const char *aname, const char *acompany, int y, int m, int d, int aprice) : Date(y,m,d)
 // Product(const char *aname, const char *acompany, int y, int m, int d, int aprice) : validto(y,m,d)
    {
        strcpy(name,aname);
        strcpy(company,acompany);
        price=aprice;
    }
    void outProduct()
    {
        printf("이름:%s\n",name);
        printf("제조사:%s\n",company);
        printf("유효기간:");
        outDate();
        //validto.outDate();
        puts("");
        printf("가격:%d\n",price);
    }
};

int main()
{
    Product shrimp("새우깡","농심",2020,8,15,900);
    shrimp.outProduct();
}

 

# 중첩 클래스

#include <stdio.h>
#include <string.h>

class Product
{
private:
    char name[24];
    char company[32];
    int price;

    //Date 클래스는 외부로 알려지지 않는 Product내의 지역클래스
    class Date
    {
    protected:
        int year, month, day;
    public:
        Date(int y, int m, int d)
        {
            year = y;
            month = m;
            day = d;
        }
        void outDate()
        {
            printf("%d,%d,%d",year,month,day);
        }
    };

Date validto;

public:
    Product(const char *aname, const char *acompany, int y, int m, int d, int aprice) : validto(y,m,d)
    {
        strcpy(name,aname);
        strcpy(company,acompany);
        price=aprice;
    }
    void outProduct()
    {
        printf("이름:%s\n",name);
        printf("제조사:%s\n",company);
        printf("유효기간:");
        validto.outDate();
        puts("");
        printf("가격:%d\n",price);
    }
};

int main()
{
    Product shrimp("새우깡","농심",2020,8,15,900);
    shrimp.outProduct();
}

 

 

 

출처 : 김상형, C++트레이닝, 한빛아카데미, 2018.03.25