Ok am in the header file I am going to post below, I i get the following errors

error C2061: syntax error : identifier 'fstream'

I get those two errors for the two methods, I searched for the error but what i found didn't help, so am here once again.

Code:
#ifndef INSURANCE_H
#define INSURANCE_H
#include "Date.h"
using std::string;
#include<string>
#include<fstream>

//Parent Class || Abstract Class
class Policy{

private:
	
	
	
	string policy_type;//Policy Type

protected:
	int pol_num;//policy number
	string pol_hol;//policy holder
	Date eff_date;//effective date of policy
	Date exp_date;//expiry date of policy

public:
	Policy();//default constructor, used to instantiate the object
	Policy(Date&, Date&,  string);//Primary Constructor For Policy
	~Policy();//Destructor
		
	//Accessors
		int getPolNum();
		string getPolHol();
		Date getEffDate();
		Date getExpDate();
		
		
		
			//Mutators
			void setPolNum(int);
			void setPolHol(string);
			void setEffDate(int, int, int);
		
			void setExpDate(int, int, int);
		
			
			
			//Calculation Method
			virtual float Premium (float)= 0;//This is the polimorphic function declaration 
			virtual void Add (fstream)=0;	
			//virtual void Delete(void)= 0;

			//virtual void Edit(void)= 0;

			
			virtual void View(fstream)= 0;
};//Closes The Class

#endif