I get error: C2501 on declaration of strings

I get error: C2501 on declaration of strings

#ifndef vid
#define vid
#include<cstring>
#include<string>
#include<string.h>
class Video
{
protected:
string title;
int id;
string genre;
string type;
string actor;
bool available;
public :
virtual double rent();
virtual void displayDetails();
};