c++类 构造函数 析构函数 拷贝构造函数

#include <bits/stdc++.h>
using namespace std;
typedef int* intpt;
int N=1;
class mybox{
    public:
        int name;
        friend class boxfri;
        friend void WatchIt(mybox box);
        mybox(int len);
        mybox(const mybox &abox);
        ~mybox();
    protected:
        intpt l,w,h;
    private:
        int MyTh;
    
};
class boxfri{
    
};
/*class boxpub: public mybox{

};
class boxpri: private mybox{

};
class boxpro: protected mybox{

};*/
mybox:: mybox(int len){
    name=N;++N;
    MyTh=12345;
    l=new int; w=new int; h=new int;
    *l=len; *w=len; *h=len;
    cout<<"We have created a box:"<<"box"<<name<<endl;
    
}
mybox:: mybox(const mybox &abox){
    l=new int; w=new int; h=new int;
    *l=*abox.l;*w=*abox.w;*h=*abox.h;
    name=abox.name;MyTh=abox.MyTh;
    cout<<"Use the copy code"<<endl;
    
}
mybox:: ~mybox(){
    delete l; delete w; delete h;
    cout<<"We have destroyed a box:"<<"box"<<name<<endl;
} 
void WatchIt(mybox box){
    cout<<"box"<<box.name<<endl;
    cout<<*box.l<<' '<<*box.w<<' '<<*box.h<<endl;
    cout<<box.MyTh<<endl;
}
int main(){
    int a;scanf("%d",&a);
    mybox box1(a);
    WatchIt(box1);
    cout<<N<<endl;
    return 0;
}

结果如下：