| Description |
CompareValue allows floating point numbers to be compared in a tolerant way. If the two numbers are close enough together, they are deemed to be equal. The delta value is the permitted tolerance.
There seems no point to the author in providing the Integer version of this function with no delta.
TValueRelationship supports the following values :
| LessThanValue | -1 |
| EqualsValue | 0 |
| GreaterThanValue | 1 |
|
|
| Related commands |
| Max |
|
Gives the maximum of two integer values |
| Min |
|
Gives the minimum of two integer values |
| Mean |
|
Gives the average for a set of numbers |
|
|
|
| Example code : Comparing floating point numbers |
// Full Unit code.
// -----------------------------------------------------------
// You must store this code in a unit called Unit1 with a form
// called Form1 that has an OnCreate event called FormCreate.
unit Unit1;
interface
uses
Math, // Unit containing the CompareValue command
Types,
Forms, Dialogs;
type
TForm1 = class(TForm)
procedure FormCreate(Sender: TObject);
end;
var
Form1: TForm1;
implementation
{$R *.dfm} // Include form definitions
procedure TForm1.FormCreate(Sender: TObject);
var
A : Single;
B : Single;
C : Single;
begin
A := 23.0;
B := 23.0;
C := 23.1;
// Compare 2 equal floats
case CompareValue(A, B) of
LessThanValue : ShowMessage('A < B');
EqualsValue : ShowMessage('A = B');
GreaterThanValue : ShowMessage('A > B');
end;
// Compare 2 unequal floats
case CompareValue(A, C) of
LessThanValue : ShowMessage('A < C');
EqualsValue : ShowMessage('A = C');
GreaterThanValue : ShowMessage('A > C');
end;
// Compare 2 unequal floats - but allow for a difference of up to +/- 0.2
case CompareValue(A, C, 0.2) of
LessThanValue : ShowMessage('A < C');
EqualsValue : ShowMessage('A = C');
GreaterThanValue : ShowMessage('A > C');
end;
end;
end.
|
| Hide full unit code |
A = B
A < C
A = C
|
|