General Info: Round Floating Point Numbers

When comparing floating point numbers, make sure you round to an acceptable level of rounding for the type of application you are using.

Languages Focus: Comparison Operators

A comparison operator compares two values either literals as in "Hello" and 3 or variables as in X and Counter. Most languages use the same operators for comparing both numbers and strings. Perl, for example, uses separate sets of comparison operators for numbers and strings.

//Does Delphi evaluate the math correctly? Yes!

//Refer to math.pas MaxSingle for more info.

if (0.1 + 0.1 + 0.1 = 0.3) then
  ShowMessage('correct')
else
  ShowMessage('not correct')

Delphi 2009 Working Example

Here's a simple working example from a button click event:

procedure TForm1.Button1Click(Sender: TObject);
var
  x: Boolean;
begin
  x := True;

  if x = True then
  begin
    ShowMessage('X was true');
  end
  else
  begin
    ShowMessage('X was false');
  end;
end;