Перевести код с Паскаля на Си

[majuw]

Uses crt;
Function CSubs(sub,s: String): Byte;
begin
  If Pos(sub,s)=0 Then
  CSubs:=0
  Else
  CSubs:=1+CSubs(sub,Copy(s,Pos(sub,s)+Length(sub),Length(s)));
end;
Var
  f: File of Char;
  i,k: Integer;
  s,str: String;
  ch: Char;
BEGIN
Clrscr;
Assign(f,'fail.dat');
Rewrite(f);
Write('Vvedite stroku simvolov: '); Readln(s);
For i:=1 to Length(s) do
Write(f,s[i]);
ch:='E'; Write(f,ch);
ch:='N'; Write(f,ch);
ch:='D'; Write(f,ch);
Reset(f);
For i:=0 to Filesize(f)-1 do
begin
  Seek(f,i);
  Read(f,ch);
  str:=str+ch;
end;
Writeln('Poluchennaya stroka: ');
Writeln(str);
Writeln('Kolichestvo "AB" = ',CSubs('AB',str));
If Pos('abcdef',str)=0 Then
Writeln('abcdef ne vhodit')
Else Writeln('abcdef vhodit');
Close(f);
Readln
END.