Program Antrian

uses wincrt;

const Max_Elemen = 10;

type antri = array[1..Max_Elemen] of char;

var Antrian : Antri;
Depan,Belakang,Pilih : integer;
Elemen : char;

procedure Kotak;
var i: integer;

begin
gotoxy(20,15);
for i := 1 to Max_Elemen*4+1 do
write('-');
gotoxy(20,16);
for i := 1 to Max_Elemen do
write('| ');
writeln('|');
gotoxy(20,17);
for i := 1 to Max_Elemen*4+1 do
write('-');
gotoxy(8,16);
write('<---Keluar');
gotoxy(22+Max_Elemen*4+1,16);
writeln('<---Masuk');
end;

procedure Letakkan(x:char; R : integer);
begin
gotoxy(18+4*R,16);
write(x);
end;

function Kosong(Q:Antri):boolean;
begin
Kosong := (Depan = Belakang);
end;

Procedure Tambah(var Antrian : Antri; X :char);
begin
{*Menambah Elemen baru*}
if Belakang = Max_Elemen then
Belakang := 1
else
Belakang := Belakang + 1;

if not(Kosong(Antrian)) then
begin
Antrian[Belakang] := X;
Letakkan(X,Belakang);
end
else
begin
gotoxy(40,9);
Write('Antrian Sudah Penuh');

repeat
{*Menunggu sampai ada penekanan tombol *}
until keypressed;

gotoxy(40,9);
write(' ':30);
Belakang := Belakang-1;
if Belakang = 0 then
Belakang := Max_Elemen;
end;
end;

function Hapus(var Antrian : Antri) : char;
begin
if Depan = Max_Elemen then
Depan := 1
else
begin
Hapus := Antrian[Depan];
Depan := Depan+1;
end;
end;
{*Program Utama*}
begin
clrscr;
Kotak;
Depan := 0;
Belakang := 0;
repeat
for Pilih := 5 to 9 do
begin
gotoxy(40,Pilih);
write(' ':39);
end;
gotoxy(1,1);
writeln('Daftar Menu Pilihan');
writeln('-------------------');
writeln;
writeln(' 1. Menambah Elemen Baru');
writeln(' 2. Menghapus Elemen');
writeln(' 3. Selesai');
writeln;
writeln;
writeln('Pilih salah satu : ');
repeat
gotoxy(22,9);
writeln(' ');
gotoxy(22,9);
readln(Pilih);
until (Pilih >=1) and (Pilih <= 3);

case Pilih of
1: begin
{* Menambah Elemen ke dalam Antrian*}
gotoxy(40,5);
writeln('Menambah Elemen');
gotoxy(40,8);
write('Isikan Elemennya : ');
readln(Elemen);
Tambah(Antrian,Elemen);
end;
2 : begin
{* Manghapus Elemen dari Antrian *}
if not(Kosong(Antrian)) then
begin
Elemen := Hapus(Antrian);
Letakkan(' ',Depan);
end
else
begin
gotoxy(30,9);
writeln('Antrian Kosong...');
Elemen := readkey;
gotoxy(30,9);
write(' ':30);
end;
end;
end;
until Pilih = 3;
end.