//单继承时的构造函数举例
#include<iostream>
using namespace std;
class B{
public:B();B(int i);~B();void print() const;
private:int b;
};
B::B(){b = 0;cout << "B's default constructor called." << endl;
}
B::B(int i){b = i;cout << "B's constructor called." << endl;
}
B::~B(){cout << "B's destructor called." << endl;
}
void B::print() const{cout << b << endl;
}
class C: public B{
public:C();C(int i, int j);~C();void print() const;
private:int c;
};
C::C(){c = 0;cout << "C's default contructor called." << endl;
}
C::C(int i, int j):B(i),c(j){cout << "C's constructor called." << endl;
}
C::~C(){cout << "C's destructor called." << endl;
}
void C::print() const{B::print();cout << c << endl;
}
int main(){C obj(5,6);obj.print();return 0;
}

//7-4派生类构造函数举例
#include<iostream>
using namespace std;
class Base1{//基类1，构造函数有参数
public:Base1(int i){cout << "Constructing Base1 " << i << endl;}
};
class Base2{//基类2，构造函数有参数
public:Base2(int j){cout << "Constructing Base2 " << j << endl;}
};
class Base3{//基类3，构造函数无参数
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), member2(d), member1(c), Base2(b){}//此处的次序与构造函数的执行次序无关
private://派生类的私有对象成员
    Base1 member1;Base2 member2;Base3 member3;
};
int main(){Derived obj(1,2,3,4);return 0;
}

//7-5派生类对象析构举例
#include<iostream>
using namespace std;
class Base1{
public:Base1(int i){cout << "Constructing Base1 " << i << endl;}~Base1(){cout << "Destructing Base1" << endl;}
};
class Base2{
public:Base2(int j){cout << "Constructing Base2 " << j << endl;}~Base2(){cout << "Destructing Base2" << endl;}
};
class Base3{
public:Base3(){cout << "Constructing Base3 *" << endl;}~Base3(){cout << "Destructing Base3" << endl;}
};
class Derived: public Base2, public Base1, public Base3{
public:Derived(int a, int b, int c, int d):Base1(a), member2(d), member1(c), Base2(b){}
private:Base1 member1;Base2 member2;Base3 member3;
};
int main(){Derived obj(1,2,3,4);return 0;
}