#include <iostream>
using namespace std;
int print() {
cout << "YYYYYYYYY\n";
}
class tt{
public:
static int (*pp)();
static int *p;
int v() {
this->pp(); //static can be ivoked by this ,but ......
}
static int vv() {
// this -> pp(); No , only static member or func can be evoked!
}
};//青年人网站编注
int (*tt::pp)() = print; //like this to initialise!
int *tt::p = NULL; //must 1. * 2. tt:: and 3. p
int main() {
tt a;
a.pp();
(*tt::pp)();
cout << sizeof(tt) << endl; //1
}
#include <iostream>
using namespace std;
void print() {
cout << "asdf\n";
}
class tt{
public:
void (*p) ();
tt() {
p = &(::print);
}
int a() {
cout << "aaaaa function!\n";
}
};
typedef int (tt::*MM)() ;
int main() {
cout << sizeof(tt) << endl; //4 not 1, void *p in class tt is a val, not a function! so sizeof is 4
tt a;
a.p();
cout << &tt::a << endl;
//cout << (int )& a.a << endl;
MM myf = &tt::a;
(a.*myf)(); //like this
}
#include <iostream>
using namespace std;
class tt {
public:
static int a;
};
int tt::a = 10;
int main() {
cout << sizeof(tt) << endl; //1, static , no matter it is const or pointer or reference! save in static section, not class
//scope!
cout << tt::a << endl;
}
#include <iostream>
using namespace std;
class tt {
public:
double a;
char b;
virtual int _a() {}
virtual int _b() {}
};
int main() {
cout << sizeof(tt) << endl; //Linux 16, Windows 24, and vptr in the beginning class!
//but align of windows is 8,because of the double,but align of the Linux is 4,even if
//u use #pragma pack(8), the align is still 4 BYTE!
}
#include <iostream>
using namespace std;
class T{
public:
char aa;
double i;
virtual int a() {}
};
int main() {
//cout << &(((T *)1)->aa) << endl; //can use it in Windows! LInux : can't
//get the aa's addr, to get that the vptr is
// at the beginning or the end of the class or the class object!
T *a = new T;
cout << (int)&(a->aa) << endl;
cout << (int)a << endl;
cout << sizeof(T) << endl;
delete a;
}
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