(* istriangle.pas - Given the lengths of 3 line segments, see if they can
 * form a triangle.  The rule is that the longest has to be shorter than the
 * sum of the other two sides.  But first, we must determine which line
 * segment is the longest.  This program illustrates the if-then statement.
 *)

program istriangle;

var
  a, b, c, longest, leg1, leg2 : integer;

begin

  (* Input *)
  writeln('Let''s see if you really have a triangle.');
  write('Enter side 1:  ');
  readln(a);
  write('Enter side 2:  ');
  readln(b);
  write('Enter side 3:  ');
  readln(c);

  (* Calculations...
   * We first determine which side is the longest, and call it longest.
   * The other two sides will be called leg1 and leg2.
   *)

  if (a > b) and (a > c) then
    begin
      longest := a;
      leg1 := b;
      leg2 := c;
    end
  else if (b > a) and (b > c) then
    begin
      longest := b;
      leg1 := a;
      leg2 := c;
    end
  else
    begin
      longest := c;
      leg1 := a;
      leg2 := b;
    end;

  (* Test for being a real triangle. *)
  if longest < leg1 + leg2 then
    writeln('Yes, this is a triangle.')
  else
    writeln('No, the three sides cannot form a triangle.');
  
end.