定义一个基类Object，有数据成员weight及相应的操作函数，由此派生出Box类，增加数据成员height和width及相应的操作函数，声明一个Box对象，观察构造函数与析构函数的调用顺序。
#include<bits/stdc++.h>
using namespace std;
class Object {
protected:
double weight;
public:
Object(double a) {
weight = a;
cout << "constructed O" << endl;
}
double func1();
~Object() {
cout << "destroyed O" << endl;
}
};
class Box :public Object {
private:
double height,width;
public:
Box(double c,double a,double b):Object(c),height(a),width(b){
cout << "constructed B" << endl;
}
~Box() {
cout << "destroyed B" << endl;
}
void dis() {
cout << "weight= " << weight << " height= " << height << " width= " << width << endl;
}
};
int main()
{
Box b1(2,3.4,6.4);
b1.dis();
}
结果为：
constructed O
constructed B
weight= 2 height= 3.4 width= 6.4
destroyed B
destroyed O