[Pascal] Tugas Struktur Data Membuat Program Queue (Antrian)

Bentuk Soal :
Buatlah program queue (antrian) dengan compiler Turbo Pascal!

Syntax Turbo Pascal

program 201543500625_pius_unindra_antrian;
uses crt;
const Max_Elemen=10;
type
    TAntri = array[1..max_elemen] of char;
var head,tail,pilih: byte; antri:TAntri;
    masukan:char;
procedure init;
var i: byte;
begin
     head:=0; tail:=0;
     for i:=1 to max_elemen do
         antri[i]:='-';
end;

function Kosong: boolean;
begin
     kosong:=(tail=0);
end;

function penuh: boolean;
begin
     penuh:=(tail=max_elemen);
end;

procedure tambahElemen(elemen:char);
begin
     if not penuh then begin
        if kosong then begin
           head:=1; tail:=1;
           end else
              inc(tail);
       antri[tail]:= elemen;
     end;
end;

function keluarkan:char;
var i: byte;
begin
     if not kosong then begin
        if tail=1 then begin
          antri[tail]:='-';
          tail:= 0; head:=0;
        end else begin
            keluarkan:=antri[head];
            for i:=head to tail-1 do begin
                antri[i]:= antri[i+1];
            end;
            dec(tail);
     end;
        if not kosong then
           antri[tail+1]:='-' else
           antri[tail]:='-';
     end;
end;

procedure tampilkan;
var i:byte;
begin
     gotoxy(10,8); writeln(' ':20);
     gotoxy(10,8);
     for i:= 1 to 10 do
         write('|',antri[i]:3);
     write('|');
end;

begin
  clrscr;
  init;
  begin
  writeln('1-Masukan Antrian');
  writeln('2-Keluarkan Antrian');
  writeln('0-Keluar');

  while not pilih <> 0 do begin
  gotoxy(1,4); write(' ':30);gotoxy(1,4);
  write('Pilihan anda?'); readln(pilih);
  case pilih of
       1: begin
          if not penuh then begin
          gotoxy(30,4); write('Masukan karakter:'); readln(masukan);
          tambahElemen(masukan);tampilkan;
          end else begin
              gotoxy(30,4); write('antrian penuh'); readln;
          end;
       end;
       2: begin
          if not kosong then begin
              gotoxy(30,4); write(keluarkan,' telah dikeluarkan');
              readln;tampilkan;
          end else begin
              gotoxy(30,4); write('Upss! Kosong'); readln;
          end;
       end;
       0:exit;
  end;
  gotoxy(30,4);writeln(' ':30);
  end;
  end;
end.