program Demonstrate_Conditional_Branching;

var One,Two,Three  : integer;
begin  (* main program *)

   One := 1;           (* these are to have some numbers *)

   Two := 2;           (* to use for illustrations *)

   Three := 3;
   if Three = (One + Two) then        (* Example 1 *)

      Writeln('three is equal to one plus two');
   if Three = 3 then begin            (* Example 2 *)

      Write('three is ');

      Write('equal to ');

      Write('one plus two');

      Writeln;

   end;
   if Two = 2 then                    (* Example 3 *)

      Writeln('two is equal to 2 as expected')

   else

      Writeln('two is not equal to 2... rather strange');
   if Two = 2 then                    (* Example 4 *)

      if One = 1 then

         Writeln('one is equal to one')

      else

         Writeln('one is not equal to one')

   else

      if Three = 3 then

         Writeln('three is equal to three')

      else

         Writeln('three is not equal to three');
end.  (* main program *)


Result of execution

three is equal to one plus two

three is equal to one plus two

two is equal to 2 as expected

one is equal to one