c ++ - the relationship between class and class

The relationship between class and class

#define _CRT_SECURE_NO_WARNINGS
#include <iostream>


using namespace std;

class A
{
public:
    void func() {
        cout << "funcA" << endl;
    }
    int a;
};

//类B拥有类A的成员变量， B has A ，//类B 依赖于 类A
class B
{
public:
    void funcB() {

    }
    A a;
};
//耦合度  高内聚 低耦合

//类C 的成员方法  需要类A的形参， C use A,//类C 依赖于 类A
class C
{
public:
    void funcC(A *a){

    }

    void funcC2()
    {

    }
};

//D继承与A    类D 如果是继承类A  类 D  is  A 。//类D继承与A 耦合度很高
class D :public A 
{
public:
    void funcD() {
        cout << this->a << endl;
    }

};

class E :public D
{

};
int main(void)
{
    

    return 0;
}