C++子類析構問題

 [cpp]
創建基類class base 

創建基類class base[cpp]
#ifndef __base_h  
#define __base_h  
class base 
{ 
public: 
    base(int a,int b); 
    ~base(); 
public: 
    int m; 
    int n; 
}; 
#endif 

#ifndef __base_h
#define __base_h
class base
{
public:
 base(int a,int b);
 ~base();
public:
 int m;
 int n;
};
#endif[cpp] 
**************base.cpp*************** 

**************base.cpp***************[cpp] view plaincopyprint?
#include "stdafx.h"  
#include "base.h"  
 
base::base(int a, int b) 
{ 
    m=a; 
    n=b; 
    printf("gou zao ji lei\n"); 
} 
 
base::~base() 
{ 
    printf("xi gou ji lei\n"); 
} 

#include "stdafx.h"
#include "base.h"

base::base(int a, int b)
{
 m=a;
 n=b;
 printf("gou zao ji lei\n");
}

base::~base()
{
 printf("xi gou ji lei\n");
}
 

**************frombase.h************

創建子類frombase繼承基類class base

[cpp] 
#ifndef __use_h  
#define __use_h  
 
#include "base.h"  
class frombase:public base 
{ 
public: 
 frombase(int q,int w,int e,int r); 
 ~frombase(); 
public: 
 int x; 
 int y; 
}; 
#endif 

#ifndef __use_h
#define __use_h

#include "base.h"
class frombase:public base
{
public:
 frombase(int q,int w,int e,int r);
 ~frombase();
public:
 int x;
 int y;
};
#endif

************frombase.cpp************

[cpp] 
#include "stdafx.h"  
#include "use.h"  
 
frombase::frombase(int q,int w,int e,int r):base(e,r) 
{ 
    x=q; 
    y=w; 
} 
frombase::~frombase() 
{ 
    printf("xi gou frombase\n"); 
} 

#include "stdafx.h"
#include "use.h"

frombase::frombase(int q,int w,int e,int r):base(e,r)
{
 x=q;
 y=w;
}
frombase::~frombase()
{
 printf("xi gou frombase\n");
}
C++ 控制台程序測試 11

[cpp] 
#include "stdafx.h"  
#include "base.h"  
#include "use.h"  
 
//int _tmain(int argc, _TCHAR* argv[])  
int main() 
{ 
 int aa =1; 
 int bb =2; 
 int cc = 3; 
 int dd = 4; 
 base* _base; 
 frombase * _frombase; 
 _base = (base*)new frombase(aa,bb,cc,dd); 
 printf("%d %d\n",_base->m,_base->n); 
 delete _base; 
 getchar(); 
 return 0; 
} 
 
執行結果：： 

#include "stdafx.h"
#include "base.h"
#include "use.h"

//int _tmain(int argc, _TCHAR* argv[])
int main()
{
 int aa =1;
 int bb =2;
 int cc = 3;
 int dd = 4;
 base* _base;
 frombase * _frombase;
 _base = (base*)new frombase(aa,bb,cc,dd);
 printf("%d %d\n",_base->m,_base->n);
 delete _base;
 getchar();
 return 0;
}

執行結果：：構造基類base

構造子類frombase

3 4

析構基類 base

 C++ 控制台程序測試 22

[cpp] 
#include "stdafx.h"  
#include "base.h"  
#include "use.h"  
int main() 
{ 
    int aa =1; 
    int bb =2; 
    int cc = 3; 
    int dd = 4; 
    base* _base; 
    frombase * _frombase; 
    _base = (base*)new frombase(aa,bb,cc,dd); 
    printf("%d %d\n",_base->m,_base->n); 
    _frombase  = (frombase*)_base; 
    printf("%d %d %d %d\n",_frombase->m,_frombase->n,_frombase->x,_frombase->y); 
    delete _frombase; 
    getchar(); 
 
    return 0; 
} 
執行結果：：： 

#include "stdafx.h"
#include "base.h"
#include "use.h"
int main()
{
 int aa =1;
 int bb =2;
 int cc = 3;
 int dd = 4;
 base* _base;
 frombase * _frombase;
 _base = (base*)new frombase(aa,bb,cc,dd);
 printf("%d %d\n",_base->m,_base->n);
 _frombase  = (frombase*)_base;
 printf("%d %d %d %d\n",_frombase->m,_frombase->n,_frombase->x,_frombase->y);
 delete _frombase;
 getchar();

 return 0;
}
執行結果：：：構造基類 base

構造子類 frombase

3 4

3 4 1 2

析構子類 frombase
析構基類 base

總結：當子類的對象直接釋放時：

            先調用子類自身的析構函數 再調用基類的析構函數

        當子類的對象被強制轉換為基類類型時：

            直接調用基類的析構函數，忽略掉子類的析構函數