if...then...else (reserved words)
If, then, and else specify the conditions under which a statement will be executed.
if expr then statement
if expr then statement else statement
If the Booleanafter if is True, the after then is executed.
Otherwise, if the else part is present, the statement after else is executed.
(* "if" statements *)
if (I < Min) or (I > Max) then I := 0;
if ParamCount <> 2 then
WriteLn('Bad command line');