#include <iostream>
#include <string>
#include <vector>
using namespace std;
typedef struct
{
int x,y;
} Point;
class PointClass
{
public:
int _x,_y;
};
int main()
{
string s;
vector<int> v;
Point a;
PointClass b;
v. // nothing happens
s. //nothing happens
a. //nothing happens
b. // works
return 0;
}