program baitapfile;

Uses crt;

Type Quanlyhoso=record

           MaCB:string[5];

           Hoten:string[20];

           Phong:string[5];

           HSL:string[5];

      end;

      DS=file of Quanlyhoso;

var f:DS; DS1,ds2:Quanlyhoso; i,n:integer;lam:char;bMaCB:string[5];

procedure TaoDS;

Begin

     writeln;

     Writeln('Nhap tong tin can bo');

     writeln;

     Assign(f,'QLHS.dat');

     rewrite(f);

     lam:='C';

     i:=1;

     repeat

           with DS1 do

                Write('Ma can bo: ');readln(MaCB);

                Write('Ho va ten: ');readln(Hoten);

                Write('Phong ban: ');readln(Phong);

                Write('He so luong: ');readln(HSL);

           end;

           i:=i+1;

           write(f,DS1);

           writeln;

           Write('Nhap tiep hay thoi? (C/K): ');readln(lam);

           writeln;

     until upcase(lam)='K';

     close(f);

     writeln;

end;

procedure Hienthi;

     writeln('          Danh sach can bo        ');

     Assign(f,'QLHS.dat');

     reset(f);

     writeln('MaCB':4,'Ho va ten':16,'Phong ban':14,'He so luong':14);

     while not eof(f) do

                with DS1 do

                     Read(f,DS1);

                     Writeln(MaCB:3,Hoten:18,Phong:10,HSL:13);

                end;

           end;

     close(f);

end;

procedure Them;

     reset(f);

     writeln('          Nhap them can bo vao danh sach    ');

     Seek(f,filesize(f));

     with DS1 do

           Write('Ma can bo: ');readln(MaCB);

           Write('Ho va ten: ');readln(Hoten);

           Write('Phong ban: ');readln(Phong);

           Write('He so luong: ');readln(HSL);

     end;

     Seek(f,filesize(f));

     write(f,DS1);

     close(f);

end;

procedure timvasua;

Var Kt:boolean;

     reset(f);

     writeln('Can bo can sua co ma la: CNP12');

     writeln;

     KT:=false;

     while not eof(f) do

          read(f,DS1);

          with ds1 do

               if MaCB='CNP12' then

                       KT:=True;

                       HSL:='2.67';

                       write('He so luong sua thanh: ',HSL:9);

                       n:=filepos(f);

                       seek(f,n-1);

                       write(f,DS1);

                  end;

      End;

     if kt=false then writeln('Khong tim thay du lieu de sua');

     close(f);

end;

procedure xoa;

var f1:ds; i:integer;KT:boolean;

     assign(f,'QLHS.dat');

     reset(f);

     assign(f1,'Dulieu1.dat');

     rewrite(f1);

     KT:=False;

     while not eof(f) do

          read(f,DS1);

          if DS1.MaCB='CNP20' then KT:=True

          else write(f1,DS1);

       end;

     if Kt=False then writeln('Trong tep ban dau khong ban ghi co ma la CNP20')

     else writeln('Tep moi la tep Dulieu1.dat');writeln;

     close(f);

     close(f1);

     erase(f);

     rename(f1,'QLHS.dat');

end;

     clrscr;

     textcolor(red);

     writeln;

     Writeln('            MENU CHUONG TRINH CHINH         ');

     writeln;

     textcolor(white);

     Writeln('                 1:Tao danh sach      ');

     Writeln('                 2:Hien thi danh sach      ');

     Writeln('                 3:Them can bo     ');

     Writeln('                 4:Tim va sua thong tin can bo     ');

     Writeln('                 5:Xoa can bo');

     Writeln('                 6:Nhan phim 9 de ket thuc    ');

     writeln;

     repeat

           writeln;

           textcolor(green);

           write('Ban chon cong viec nao?   ');readln(n);

           writeln;

           textcolor(white);

           case n of

                1:TaoDS;

                2:Hienthi;

                3:begin Them; Hienthi; end;

                4:begin TimvaSua; Hienthi; end;

                5:begin xoa; Hienthi; end;

           end;

     until n=9;

end.