C++ 结构指针

 1 #include<iostream>
  2 using namespace std;
  3 //结构变量.*成员指针 ， 结构指针->*成员指针
  4 struct date{
  5         int year;
  6         int month;
  7         int day;
  8         void print(){cout<<year<<" - "<<month<<" - "<<day<<endl;}
  9 };
 10 void f(double d){cout<<d<<endl;}
 11 void showmember(date a[],int n,int date::*p)
 12 {
 13         for(int i = 0;i<n;i++)
 14         {
 15                 cout<<a[i].*p<<"  ";//*(a+i).*p == (a+i)->*p;
 16         }
 17         cout<<endl;
 18 }
 19 int main()

 20 {

21         date a[5] = {{2012,3,2},{2019,4,1},{2014,3,19},{2012,9,21},{1999,12,    18}};
 22         date d = {1992,11,4};
 23         cout<<"&d = "<<&d<<endl;
 24         cout<<"&d.year = "<<&d.year<<",&d.month = "<<&d.month<<",&d.day = "<    <&d.day<<endl;
 25         cout<<&date::year<<&date::month<<&date::day<<endl;
 26 //      cout<<&main<<&f<<endl;
 27         union
 28         {
 29                 int n;
 30                 int date::*mp;
 31         };
 32         mp = &date::day;
 33         cout<<" n = "<<n<<endl;
 34         cout<<d.*mp<<endl;
 35         mp = &date::year;
 36         cout<<d.*mp<<endl;

37         showmember(a,5,&date::month);
 38         showmember(a,5,&date::year);
 39         showmember(a,5,&date::day);
 40         d.print();
 41         a[3].print();
 42         void(date::*pf)() = &date::print;
 43         (d.*pf)();
 44         (a->*pf)();
 45 
 46         return 0;
 47 }