function H(Text,Key: String; Encode: boolean): String;
var
  i, KeyLength: integer;
  Sign: ShortInt;
begin
 KeyLength:=Length(Key);
 if Encode then Sign :=-1 else Sign:=1;
 for i:=1 to Length(Text) do
  Text[i]:=chr(ord(Text[i])+Sign*ord(Key[i mod KeyLength+1]));
  Result:=Text;
end;

var
 y, x: Real;
begin
y := exp(6*x + ln(3)) + (exp(2*x + ln(4)) - exp(8*x +ln(5)));

var
  x1, y1, z1: Integer;
  X, O, Y: Real; 
  P: Real;
...


procedure entercoord(x1,y1,z1: Integer);
begin
  writeln('Vvedite koordinaty x1, y1, z1');
  readln(x1,y1,z1);
end;

procedure CalcVolCyl;

procedure scr;
begin
  clrscr;
  writeln('Vivodim na ekran'); {Типа так}
end;

procedure prnt;
var
  f: Text;
  i: Integer;
begin
  clrscr;
  writeln('Gelaete vyvesti na printer nagmite: <Y> ili <N> else nado vyiti');
  readln(ch);
  if (ch = 'Y) or (ch = 'y') then 
  begin
    assign(f, 'prn');
    rewrite(f);
    write('out on printer');
    close(f);
  end
  else
    for i:=0 to 15 do delay(3000);
    
end;

begin
  {vycheslenie obiema cilindra}
  
end;


begin
  writeln('');
  writeln('');
  writeln('');
  readln(i);
  ...
  {В зависимости от введенного параметры выполняем действие}
end;