C++_多重继承（多个父类或基类）

C++_多重继承（多个父类或基类）

1、简单实现多重继承
注意：沙发床继承沙发和床

#include 
#include 
#include 

using namespace std;

class Sofa {
public:
	void watchTV(void) { cout<<"watch TV"<<endl; }
};

class Bed {
public:
	void sleep(void) { cout<<"sleep"<<endl; }
};

class Sofabed : public Sofa, public Bed {
};

int main(int argc, char **argv)
{
	Sofabed s;
	s.watchTV();
	s.sleep();
	return 0;
}
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26

2、多重继承造成的二义性的问题
注意：沙发也有重量的床也有重量，当派生类沙发床想要，设置重量时候不知道改调用哪一个

#include 
#include 
#include 

using namespace std;

class Sofa {
private:
	int weight;
public:
	void watchTV(void) { cout<<"watch TV"<<endl; }
	void setWeight(int weight) { this->weight = weight; }
	int getWeight(void) const { return weight; }
};

class Bed {
private:
	int weight;
public:
	void sleep(void) { cout<<"sleep"<<endl; }
	void setWeight(int weight) { this->weight = weight; }
	int getWeight(void) const { return weight; }
};

class Sofabed : public Sofa, public Bed {
};

int main(int argc, char **argv)
{
	Sofabed s;
	s.watchTV();
	s.sleep();

	//s.setWeight(100); /* error, 有二义性 */
	s.Sofa::setWeight(100);
	
	return 0;
}
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38

3、解决二义性的问题（引入虚拟继承）
注意：虚拟继承架构

虚拟继承的内存情况

#include 
#include 
#include 

using namespace std;

class Furniture {
private:
	int weight;
public:
	void setWeight(int weight) { this->weight = weight; }
	int getWeight(void) const { return weight; }
};

class Sofa : virtual public Furniture {
private:
	int a;
public:
	void watchTV(void) { cout<<"watch TV"<<endl; }
};

class Bed : virtual public Furniture {
private:
	int b;
public:
	void sleep(void) { cout<<"sleep"<<endl; }
};

class Sofabed : public Sofa, public Bed {
private:
	int c;
};

int main(int argc, char **argv)
{
	Sofabed s;
	s.watchTV();
	s.sleep();

	s.setWeight(100);
	
	return 0;
}
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43