派生类的构造-析构函数

子类的构造函数当中  参数列表应该含有 基类及子类的全部数据成员.

派生类的构造-析构顺序:

构造函数:先 基类 ;后子类;

析构函数:先 子类 ;后基类;

实例1:

// 派生类-构造函数.cpp : 定义控制台应用程序的入口点。
//

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

class BaseEntity
{
protected:
 int m1;
 int m2;
public:
 BaseEntity(int i,int j)
 {
  cout << "base class constructor." <<endl;
  m1 = i;
  m2 = j;
 }
};
////
class Derived:public BaseEntity
{
private:
 int m3;
 int m4;
public:
 Derived(int i,int j,int m,int n):BaseEntity(i,j)//注意i,j顺序..
 {
  cout <<"derived class constructor."<<endl;
  m3 = m;
  m4 = n;
 }
 void printMember()
 {
  cout<<"m1: "<< m1 <<endl
   <<"m2: "<< m2 <<endl
   <<"m3: "<< m3 <<endl
   <<"m4: "<< m4 <<endl;
 }
};
////
int _tmain(int argc, _TCHAR* argv[])
{
 Derived d(1,2,3,4);
 d.printMember();

 getchar();
 return 0;
}

实例2:

// 派生类-析构函数.cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"
#include <iostream>
using namespace std;
class BaseEntity
{
public:
 BaseEntity()
 {
  cout<<"base class constructor." <<endl;
 }
 ~BaseEntity()
 {
  cout<<"base class destructor." <<endl;
 }
};
///
class Derived:public BaseEntity
{
public:
 Derived()
 {
  cout<<"derived class constructor." <<endl;
 }
 ~Derived()
 {
  cout<<"derived class destructor." <<endl;
 }
};

int _tmain(int argc, _TCHAR* argv[])
{
 Derived d;
// getchar();
 return 0;
}