Задача "Очередь"

program n1 ;
uses crt;
type mas=array[0..100] of integer;
var c:char;
  j,i,n,head:integer;
  a: mas;
  flag:boolean;
procedure read_from_queue(a: mas;var i,j: integer);
begin
if (i=j) and (flag)  then writeln('Queue is empty')
else
 begin
  writeln (a[i]:2);
  if i=n then
  begin
  i:=1;
  flag:=false;
  end
  else
  inc(i);
 end
end;
 
procedure write_to_queue(var a: mas; var j,i,n: integer);
begin
if (j=i) and (not flag) then writeln('Queue is full')
else
begin
readln(a[j]);
If j>n then
begin
j:=1;
flag:=false;
end
else
inc(j);
end
end;
 
procedure print_queue(a: mas; i,j: integer);
var k:integer;
begin
if not flag then
for K:=i to j-1 do write (a[k],' ')
else
begin
for k:=i to n do
write(a[k],' ');
for k:=1 to j-1 do
write(a[k],' ');
end;
writeln
end;
 
procedure print_mas(a: mas;head:integer );
var h:integer;
begin
for h:=1 to head do
write (a[h]:3);
writeln
end;
Begin
flag:=true;
i:=0;
j:=0;
clrscr;
writeln('1-zapis elementa u Queue');
writeln('2-Prochitatu vmist zi Queue');
writeln('3-pokazati vmist Queue');
writeln('4-pokazati vmist masivu');
writeln('Esc-zaverchitu robotu');
writeln ('iput n');
readln (n);
 
repeat
begin
 
writeln;
c:=readkey;
 
case c of
'1': write_to_queue(a,j,i,n);
'2': begin  read_from_queue(a,i,j) ;
end;
'3':begin writeln('Queue'); print_queue(a,i,j) ;
 
 
    end;
'4' :begin  writeln('masiv'); print_mas(a,head);
 
end;
end;
end;
 
 
until c=#27;
 
 
 end.