C++结构体中的静态变量

分享一个挺有意思的代码：

 #include <bits/stdc++.h>
 using namespace std;

 struct Point {
     static int cnt;
     Point() {
         ++cnt;
         cout << "There is " << cnt << " item(s)." << endl;
     }
     ~Point() {
         --cnt;
         cout << cnt << " item(s) remains." << endl;
     }
 } ;
 int Point::cnt;

 int main() {
     Point a, b;
     delete (new Point());
     Point c, d;
     return ;
 }

java是可以直接在类中初始化的，不过C++的初始化要在结构体外完成，否则会在链接的时候发生找不到对象的错误。

 #include <bits/stdc++.h>
 using namespace std;

 class TheOnlyInstance {
     public:
         static TheOnlyInstance *GetTheOnlyInstance();
         static int Parameter;
     protected:
         TheOnlyInstance() {}
 } ;

 //int TheOnlyInstance::Parameter = 2;

 TheOnlyInstance *TheOnlyInstance::GetTheOnlyInstance() {
     static TheOnlyInstance objTheonlyInstance;
     int Parameter = ;
     return &objTheonlyInstance;
 }

 int main() {
     //cout << TheOnlyInstance::Parameter << endl;
     cout << TheOnlyInstance::GetTheOnlyInstance() << endl;
     cout << TheOnlyInstance::Parameter << endl;
     return ;
 }

——Written by Lyon