104.virtual虚函数多态与异构数据结构

#include "mainwindow.h"
#include <QApplication>
#include <list>
#include <QPushButton>
#include<QLabel>
#include<QLineEdit>

using namespace std;

//异构数据结构,每个数组元素都是基类指针
//异构链表,每一个结点都是基类的指针,指向了派生类
//基类指针基于多态与虚函数调用派生类的方法

class object
{
public:
    virtual void showit()
    {

    }
};

class mywindow:public object
{
public:
    MainWindow *p;

    mywindow()
    {
        p = new MainWindow;
    }

    void showit()
    {
        p->show();
     }
};

class mylabel:public object
{
public:
    QLabel *p;
    mylabel()
    {
        p=new QLabel;
    }
    void showit()
    {
        p->show();
    }
};

class myedit:public object
{
public:
    QLineEdit *p;
    myedit()
    {
        p=new QLineEdit;
    }
    void showit()
    {
        p->show();
    }
};

class mybutton:public object
{
  public:
    QPushButton *p;
    mybutton()
    {
        p = new QPushButton;
    }

    void showit()
    {
        p->show();
    }
};

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);

    list<object *>mylist;

    object *p = new mywindow;
    mylist.push_back(p);

    p = new mylabel;
    mylist.push_back(p);

    p = new mybutton;
    mylist.push_back(p);

    p = new mybutton;
    mylist.push_back(p);

    for(auto it:mylist)
    {
        (*it).showit();
    }
    return a.exec();
}