问链表只记得最近添加的对象。

EN

#include "ShapeList.h"
#include <iostream>

using namespace std;

int main()
{
    ShapeList list;
    list.add(Rectangle(0,0,2,5));
    list.print();
}

#ifndef SHAPELIST_H
#define SHAPELIST_H
#include "Shape.h"
#include "Rectangle.h"

class ShapeList
{
private:
    Shape *conductor; //this will point to each node as it traverses the list
    Shape *root; //the unchanging first node
public:
    ShapeList();
    void print();
    void add(const Shape &s);
};

#endif

#include "ShapeList.h"
#include <iostream>
using namespace std;

ShapeList::ShapeList()
{
    cout << "ShapeList created" << endl;
    root = new Shape; //now root points to a node class
    root->next = 0; //the node root points to has its next  pointer set to equal a null pointer
    conductor = root; //the conductor points to the first node
}

void ShapeList::add(const Shape &s)
{
    cout << "Shapelist's add function called" << endl;
    conductor->next = new Shape; //creates node at the end of the list
    conductor = conductor->next; //goes to next node
    Shape *pShape = s.clone(); //get a pointer to s
    conductor->current = pShape; //points current to pShape point
    conductor->next = 0; //prevents loops from going out of bounds
}

void ShapeList::print()
{
    conductor = root; //the conductor points to the start of the linked list
    if(conductor != 0)
    {
        while(conductor->next != 0)
        {
            conductor = conductor->next;
            cout << conductor->current->width << endl;
        }
        //cout << conductor->current->width << endl;
    }
}

Rectangle * Rectangle::clone() const
{
    cout << "Rectangle's clone function called" << endl;
    Rectangle copiedRect(this);
    Rectangle * pCopiedRect = &copiedRect;
    return pCopiedRect;
}

Rectangle::Rectangle(const Rectangle *ref)
{
    cout << "Rectangle's copy constructor called" << endl;
    this->x = ref->x;
    this->y = ref->y;
    this->width = ref->width;
    this->height = ref->height;
}