C++一个多态代码实例

C++中经常使用基类和派生对象多态的特性实现一些数据的传输，基类为纯虚类的接口类，派生类继承接口类。以下实现了一个典型的多态实例，该实例可以应用在软件开发中两个类的数据传输中。下面直接上代码：

/*
 * Description： 一种使用纯虚类接口实现数据回调的方式
 * Date：        xxxx-xx-xx
 * 
 **/

#include <iostream>

using namespace std;

/* 纯虚基类接口 */
class ICRtpListen
{
private:
    /* data */

public:
    ICRtpListen(/* args */);
    ~ICRtpListen();

    int firstFunction0();
    virtual int onConnect() = 0;
    virtual int onDataIn() = 0;
};

ICRtpListen::ICRtpListen(/* args */)
{
    printf("ICRtpListen\n");
}

ICRtpListen::~ICRtpListen()
{
    printf("~ICRtpListen\n");
}

/* 派生类 */
class CRtpServer1: public ICRtpListen
{
private:
    /* data */

public:
    CRtpServer1();
    CRtpServer1(ICRtpListen *pBaseObj);
    ~CRtpServer1();

    int firstFunction1();
    virtual int onConnect();
    virtual int onDataIn();

public:
    ICRtpListen *pBaseRtpObj; // 一个基类指针成员
};

CRtpServer1::CRtpServer1()
{
    printf("CRtpServer1\n");
}

CRtpServer1::CRtpServer1(ICRtpListen *pBaseObj)
{
    pBaseRtpObj = pBaseObj; // 保存基类指针
    printf("CRtpServer1\n");
}

CRtpServer1::~CRtpServer1()
{
    printf("~CRtpServer1\n");
}

int CRtpServer1::onConnect()
{
    pBaseRtpObj->onConnect();
    printf("CRtpServer1 onConnect in\n");
    return 0;
}

int CRtpServer1::onDataIn()
{
    pBaseRtpObj->onDataIn();
    printf("CRtpServer1 cb data coming in...\n");
    return 0;
}

/* 数据处理类 */
class CProcessServer2: public ICRtpListen
{
private:
    /* data */

public:
    CProcessServer2();
    ~CProcessServer2();

    int firstFunction1();
    virtual int onConnect();
    virtual int onDataIn();
};

CProcessServer2::CProcessServer2(/* args */)
{
    printf("CProcessServer2\n");
}

CProcessServer2::~CProcessServer2()
{
    printf("~CProcessServer2\n");
}

int CProcessServer2::onConnect()
{
    printf("CProcessServer2 onConnect\n");
}

int CProcessServer2::onDataIn()
{
    printf("CProcessServer2 onDataIn\n");
    return 0;
}

int main()
{
    CProcessServer2 *pProcessObj = new CProcessServer2;
    CRtpServer1 *pRtpSvr = new CRtpServer1(pProcessObj);

    cout << "==============================" << endl;
    pRtpSvr->onConnect();
    pRtpSvr->onDataIn();
    cout << "==============================" << endl;
    delete pProcessObj;
    delete pRtpSvr;
    printf("\033[0m""[%s|%d] main exit\n", __FUNCTION__, __LINE__);

    return 0;
}

编译命令：g++ virtual-fun-interface.cpp -o demo

运行结果：

 

 

 双等号线中间可以看出函数调用关系，在pRtpSvr中调用成员函数发生了多态。