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1. 派生类（子类）重写父类方法

1.1 例如父类是24小时制的

class CTime{public:    int getHour();

1.2 子类定义为12小时制

#ifndef CURRENT_TIME_H#define CURRENT_TIME_H#include "Time.h"// 子类 CCurrentTime 继承父类 Ctimeclass CCurrentTime : public CTime{
   public:    // 构造函数    CCurrentTime();    // 析构函数    ~CCurrentTime();    void init();    int getHour();};#endif

1.3 重写方法

// 子类重写父类的getHour方法// 返回 12 小时制int CCurrentTime::getHour() {    int mHour = CTime::getHour();    cout<<"CCurrentTime getHour = "<
   
    <
    
      12) {        return mHour - 12;    }}
    
   

1.4 运行结果

#include 
   
    #include "Time.h"#include "CurrentTime.h"using namespace std;int main() {    CCurrentTime curTime;    curTime.init();    cout<
    
     <<":"<
     
      <<":"<
      
       <
      
     
    
   

2. Has 关系-整体与部分关系

类包含其他类

#ifndef DATE_TIME_H#define DATE_TIME_H#include "Time.h"class CDateTime {
   public:    CDateTime();    ~CDateTime();    CDateTime(int year, int month, int day,            int hour, int minute, int second);    void display();private:    int m_nYear;    int m_nMonth;    int m_nDay;    // has 包含关系，类包含其他类    CTime m_ntime;};#endif

调用被包含函数的方法进行赋值

#include "DateTime.h"#include 
   
    using namespace std;CDateTime::CDateTime(){}CDateTime::~CDateTime(){}CDateTime::CDateTime(int year, int month, int day,        int hour, int minute, int second){    m_nYear = year;    m_nMonth = month;    m_nDay = day;    m_ntime.setHour(hour);    m_ntime.setMinute(minute);    m_ntime.setSecond(second);}void CDateTime::display(){    cout<
    
     <<"-"<
     
      <<"-"<
      
       <<" "<
       
        <<":"<
        
         <<":"<
         
          <
         
        
       
      
     
    
   

运行实例

#include 
   
    #include "DateTime.h"using namespace std;int main() {    CDateTime mCDateTime(2018, 5, 20, 8, 8, 8);    mCDateTime.display();    return 0;}
   

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