多重继承中派生类的构造函数和析构函数

#include<iostream>
using namespace std;
class Base1
{
public:
Base1(int i)
{
cout<<"Constructing Base1 "<<i<<endl;
}
};
class Base2
{
public:
Base2(int j)
{
cout<<"Constructing Base2 "<<j<<endl;
}
};
class Base3
{
public:
Base3()
{
cout<<"Constructing Base3 *"<<endl;
}
};
class Derived:public Base1,public Base2,public Base3
{
public:
Derived(int a,int b,int c,int d):Base1(a),Base2(b),number1(c),number2(d){}
private:
Base1 number1;
Base2 number2;
Base3 number3;
};
int main()
{
Derived obj(1,2,3,4);
return 0;
}

运行结果：



心得：

1、调用基类构造函数，调用顺序按照他们被继承时声明的顺序（从左向右）

2、对本类成员初始化列表中的基本类型成员和对象成员进行初始化，初始化的顺序按照他们在类中声明的顺序，对象成员初始化是自动调用对象所属类的构造函数完成。

3、执行派生类的构造函数体的内容。

对比：

#include<iostream>
using namespace std;
class Base1
{
public:
Base1(int i)
{
cout<<"Constructing Base1 "<<i<<endl;
}
};
class Base2
{
public:
Base2(int j)
{
cout<<"Constructing Base2 "<<j<<endl;
}
};
class Base3
{
public:
Base3()
{
cout<<"Constructing Base3 *"<<endl;
}
};
class Derived:public Base2,public Base1,public Base3
{
public:
Derived(int a,int b,int c,int d):Base1(a),Base2(b),number1(c),number2(d){}
private:
Base1 number1;
Base2 number2;
Base3 number3;
};
int main()
{
Derived obj(1,2,3,4);
return 0;
}

运行结果：