ошибка

#include <fstream.h>
#include <stdlib.h>
#include <conio.h>
#include  <iomanip.h>
 class Diski {
struct DISK
{
char name[100],format[20];
int size,price,speed;
}  ;
fstream f;
public:
void swap(DISK &q1, DISK &q2);
void PrintFile();
void WriteToFile(int q);
void FileRewrite();
void Sort();
} ;
void Diski::swap(DISK &q1, DISK &q2)
{
DISK x;
x=q1;
q1=q2;
q2=x;
}
 
 
 
 
void Diski::PrintFile()
{
DISK m;
f.open("1.dat",ios::in);
cout<<("                Name    format      size    price     speed\n") ;
while(!f.eof())
 {
f>>m.name>>m.format>>m.size>>m.speed>>m.price;
if (f.peek()!=EOF)
cout<<setw(20)<<m.name<<setw(10)<<m.format<<setw(10)<<m.size<<setw(10)<<m.price<<setw(10)<<m.speed<<"\n";
}
  f.close();
  cout<<"\nComplite\nPress any key to continue....";
getch();
 
 
}
 
 
void Diski::WriteToFile(int q)
{
DISK m;
f.open("1.dat",ios::app);
for (int i=0;i<q;i++)
{
cout<<"Vvedite nazvanie diska\n"; cin>>m.name;
cout<<"Vvedite format diska\n"; cin>>m.format;
cout<<"Vvedite razmer diska\n"; cin>>m.size;
cout<<"Vvedite cheny diska\n"; cin>>m.price;
cout<<"Vvedite skorost' diska\n";cin>>m.speed;
f<<m.name<<"\t"<<m.format<<"\t"<<m.size<<"\t"<<m.price<<"\t"<<m.speed<<"\n";
system("cls");
}
f.close();
cout<<"Complite\nPress any key to continue....";
getch();
system("cls");
}
 
void Diski::FileRewrite()
{
f.open("1.dat",ios::out); f.close();
cout<<"Complite\nPress any key to continue...." ;
 getch();
 
}
 
void Diski::Sort()
{
int n;
DISK m[100];
int q,i,j;
system("cls");
cout<<"Po kakomy poly sortirovat':\n";
cout<<"1 - Razmer\n";
cout<<"2 - chena\n";
cout<<"3 - skorost'\n";
cin>>q;
f.open("1.dat",ios::in);
i=-1;
while (!f.eof())
{
i++;
f>>m[i].name>>m[i].format>>m[i].size>>m[i].price>>m[i].speed;
 
}
n=i;
for (i=0; i<n; i++)
for (j=1; j<n;j++)
{
if (q==1&&m[j].size<m[j-1].size) swap(m[j],m[j-1]);
if (q==2&&m[j].price<m[j-1].price) swap(m[j],m[j-1]);
if (q==3&&m[j].speed<m[j-1].speed) swap(m[j],m[j-1]);
}
cout<<("                Name    format      size     price     speed\n") ;
 
for (i=0;i<n;i++)
cout<<setw(20)<<m[i].name<<setw(10)<<m[i].format<<setw(10)<<m[i].size<<setw(10)<<m[i].price<<setw(10)<<m[i].speed<<"\n";
f.close();
cout<<"\nComplite\nPress any key to continue....";
getch();
}
 
 
 
int main()
{
int d,n;
Diski clas;
do
{
system("cls");
cout<<("Viberite deistvie:\n");
cout<<("------------------\n");
cout<<("1 - WriteToFile()\n");
cout<<("2 - FileRewrite()\n");
cout<<("3 - Sort()\n");
cout<<"4 - PrintFile()\n" ;
cout<<("5 - Exit\n");
cin>>d;
switch (d)
{
case 1: cout<<"Kolichestvo zapicei\n";cin>>n; clas.WriteToFile(n); break;
case 2:clas.FileRewrite(); break;
case 3:  clas.Sort(); break;
case 4:clas.PrintFile(); break;
case 5: return 0;
}
 
 
}
while (1);
}