Tạo in xóa trong con trỏ

uses crt;
type
  contro= ^phantu;
  phantu = record
    hoten: string[30];
    tuoi:integer;
    diemtb:integer;
    next: contro;
  end;
var
  first:contro;
  i,cn:integer;
  ch:char;
procedure taods;
var p:contro;
begin
  first:=nil;
  i:=1;
  repeat
    new(p);
    write('nhap ho ten: ');readln(p^.hoten);
    write('nhap tuoi: ');readln(p^.tuoi);
    write('nhap diem tb: ');readln(p^.diemtb);
    p^.next :=first;
    first:=p;
    i:=i+1;
    writeln('co muon nhap nua ko? c/k');readln(ch);
  until ch = 'k';
end;
procedure inds;
var p:contro;
begin
  p:=first;
  i:=1;
  writeln('stt hoten tuoi diemtb');
  while p<>nil do
    begin
      writeln(i:3,p^.hoten:7,p^.tuoi:3,p^.diemtb:4);
      p:=p^.next;
      i:=i+1;
    end;
end;
procedure xoapt;
var
  p,q:contro;
  ten1:string[30];
begin
  write('nhap ten sinh vien can xoa: ');readln(ten1);
  p:=first;
  while (p<>nil )and (p^.hoten<>ten1) do p:=p^.next;
  if p=nil then write('khong co ten trong danh sach')
  else
    begin
      write('co ten trong danh sach');
      new(q);
      q:=first;
      while q^.next <> p do q:=q^.next;
      q^.next:=p^.next;
      dispose(p);
    end;
end;


BEGIN
  Clrscr;
  repeat
    writeln('Danh sach chuc nang');
    writeln('1. Tao danh sach');
    writeln('2. In danh sach');
    writeln('3. Xoa danh sach');
    writeln('4. Thoat');
    writeln('Xin moi chon chuc nang: ');readln(cn);
    case cn of
      1: taods;
      2: inds;
      3: xoapt;
    end;
  until cn= 4;
  readln;
end.