#include"iostream.h"
class CObject
{
public:
  static int a;
  CObject();
  ~CObject();
  void Fun();
private: 
int m_count; 
int m_index;
};
VoidCObject::Fun(){  cout<<"Fun\n"<<endl;}
CObject::CObject(){  cout<<"Construct!\n";}
CObject::~CObject(){  cout<<"Destruct!\n";}
int CObject::a=1;
void main(){
cout<<"Sizeof(CObject):"<<sizeof(CObject)<<endl; cout<<"CObject::a="<<CObject::a<<endl;
CObject myObject;cout<<"sizeof(myObject):"<<sizeof(myObject)<<endl;
cout<<"sizeof(int)"<<sizeof(int)<<endl;
}

Sizeof(CObject):8
CObject::a=1
Construct!
sizeof(myObject):8
sizeof(int)4
Destruct!

class CObject
{
public:
static int a;
CObject();
~CObject();
void Fun();
private:
double m_count; //这里改成了double
int m_index;
};
这个类用sizeof()测出来的大小是 2*sizeof(double)=16
 
class CObject
{
public:
static int a;
CObject();
~CObject();
void Fun();
private:
char m_count; //这里改成了char
int m_index;
};
大小是2*sizeof(int)=8
class CObject
{
public:
static int a;
CObject();
~CObject();
void Fun();
private:
double m_count; //这里改成了double
int m_index;
char c;
};
sizeof(char)+sizeof(int) <sizeof(double) 所以大小是2*sizeof(double)

class Base 
{ 
public: 
  Base(); 
  ~Base(); 
}; 
 class Base {
 public:
Base();
 ~Base();
 };

class Base 
{ 
public: 
  Base();         
  virtual ~Base();     //每个实例都有虚函数表 
  void set_num(int num)  // 普通成员函数，为各实例公有，不归入sizeof统计 
  { 
    a=num; 
  } 
private: 
  int a;         //占4字节 
  char *p;         //4字节指针 
}; 
  
class Derive:public Base 
{ 
public: 
  Derive():Base(){};   
  ~Derive(){}; 
private: 
  static int st;     //非实例独占 
  int d;           //占4字节 
  char *p;          //4字节指针 
};  
int main() 
{ 
  cout<<sizeof(Base)<<endl; 
  cout<<sizeof(Derive)<<endl; 
  return 0; 
} 
 class Base {
 public:
Base();
virtual ~Base(); //每个实例都有虚函数表
void set_num(int num) { a=num; } //普通成员函数，为各实例公有，不归入sizeof统计
private:
 int a; //占4字节
char *p; //4字节指针
};
class Derive:public Base {
public:
Derive():Base(){};
~Derive(){};
private:
static int st; //非实例独占
int d; //占4字节
char *p; //4字节指针
};
int main() {
cout<<sizeof(Base)<<endl;
cout<<sizeof(Derive)<<endl;
 return 0;
}

class Derive:public Base
 
{
 
public:
 
  Derive():Base(){};
 
  ~Derive(){};
 
private:
 
  static int st;
 
  int d;
 
  char *p;
 
  char c;
 
};
 
 class Derive:public Base {
 
public:
 
 Derive():Base(){};
 
 ~Derive(){};
 
private:
 
static int st;
 
 int d;
 
char *p;
 
 char c;
 
};