Ошибка в программе. Структура "Автомобиль"

//---------------------------------------------------------------------------
 
#include <vcl.h>
#pragma hdrstop
#include <iostream.h>
#include <conio.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
//---------------------------------------------------------------------------
struct ant
{
int kod;
char mark[15];
char fam[15];
double nomer;
};
FILE *f,*g;
ant x;
 
//stvorenn9
void stv(void)
{ if ((f=fopen("x.dat","w"))==NULL)
{perror("Fail uje suwestvuet");
getch();
exit(1);
}
cout<<"\n Vvedite inform avtomobilya\n";
do
{cout<<"\n Vvedite marku avtomobilya: ";
cin>>x.mark;
cout<<"\n Vvedite nomer avtomobilya: ";
cin>>x.nomer;
cout<<"\n Vvedite familiu vladelca: ";
cin>>x.fam;
fwrite(&x,sizeof(x),1,f);
}
while(getch()!=27);
fclose(f);
}
 
//dopolnenie
void dop(void)
{ if ((f=fopen("x.dat","a"))==NULL)
{perror("Fail uje sywestvuet");
getch();
exit(1);
}
cout<<"\n Vvedite inform avtomobilya\n";
do
{cout<<"\n Vvedite marku avtomobilya: ";
cin>>x.mark;
cout<<"\n Vvedite nomer avtomobilya: ";
cin>>x.nomer;
cout<<"\n Vvedite prizvuwe vladelca: ";
cin>>x.fam;
fwrite(&x,sizeof(x),1,f);
}
while(getch()!=27);
fclose(f);
}
 
//peresmotr
void per(void)
{ if ((f=fopen("x.dat","r"))==NULL)
{perror("Fail uje suwestvuet");
getch();
exit(1);
}
cout<<"\n Vvedite inform avtomobilya: \n";
while(fread(&x,sizeof(x),1,f)!=NULL)
{cout<<"\n Vvedite marku avtomobilya: "<<x.mark;
cout<<"\n Vvedite nomer avtomobilya: "<<x.nomer;
cout<<"\n Vvedite prizvuwe vladelca: "<<x.fam;
getch();
}
fclose(f);
}
 
//DEl
void del(void)
{ if ((f=fopen("x.dat","r"))==NULL)
{perror("Fail uje suwestvuet");
getch();
exit(1);
}
if((g=fopen("x1.dat","w"))==NULL)
{perror("Fail uje suwestvuet");
getch();
exit(1);
}
cout<<"\n Vvedite inform avtomobilya: \n";
while(fread(&x,sizeof(x),1,f)!=NULL)
{cout<<"\n Vvedite marku avtomobilya: "<<x.mark;
cout<<"\n Vvedite nomer avtomobilya: "<<x.nomer;
cout<<"\n Vvedite prizvuwe vladelca: "<<x.fam;
cout<<"\n\n UDALITE(y/n)?";
if(getch()=='n') fwrite(&x,sizeof(x),1,g);
}
fclose(f);
fclose(g);
unlink("x.dat");
rename("x1.dat","x.dat");
}
 
//dolg
void count(void)
{ char vodmark[15];
if((f=fopen("x.dat","r"))==NULL)
{perror("Fail uje sywestvuet");
getch();
exit(1);
}
cout<<"\nvvedite marku\n";
cin>>vodmark;
 int k=0;
while(fread(&x,sizeof(x),1,f))
if(vodmark==x.mark) k++;
cout<<"\n Kolichestvo marok: "<<k;
getch();
}
#pragma argsused
int main(int argc, char* argv[])
{
 int r;
clrscr();
do
{
clrscr();
cout<<"\n\n\n\t\t GLAVNOE MEHU \n\t1-SOZDANIE\n\t2-PERESMOTR";
cout<<"\n\t3-DOPOLNENIE\n\t4-DELETE\n\t5-PODSCHET\n\t6-BUXOD\n\t REGUM?\n\t";
cin>>r;
switch(r)
{case 1:{stv();break;}
case 2:{per();break;}
case 3:{dop();break;}
case 4:{del();break;}
case 5:{count();break;}
case 6:exit(1);
}
}
while(1);
 
        return 0;
}
//---------------------------------------------------------------------------