Unicode tip-Integer and Float To AnsiString

SysUtils defines the well-known IntToStr and FloatToStr, which return a Unicode String - but not an AnsiString. If you want to use AnsiStrings in your application, you may want to use versions of these routines that return an AnsiString. Since these didn’t exist, yet, I’ve written a set of routines to help us converting integers and floats to AnsiStrings, based on the built-in Str function.

unit Convert;
interface

function IntToAnsiStr(X: Integer; Width: Integer = 0): AnsiString;

function FloatToAnsiStr(X: Extended; Width: Integer = 0;
   Decimals: Integer = 0): AnsiString; overload;
function FloatToAnsiStr(X: Double; Width: Integer = 0;
   Decimals: Integer = 0): AnsiString; overload;
function FloatToAnsiStr(X: Single; Width: Integer = 0;
   Decimals: Integer = 0): AnsiString; overload;

implementation

function IntToAnsiStr(X: Integer; Width: Integer = 0): AnsiString;
begin
   Str(X: Width, Result);
end;

function FloatToAnsiStr(X: Extended; Width: Integer = 0;
   Decimals: Integer = 0): AnsiString;
begin
   Str(X: Width: Decimals, Result);
end;

function FloatToAnsiStr(X: Double; Width: Integer = 0;
   Decimals: Integer = 0): AnsiString;
begin
   Str(X: Width: Decimals, Result);
end;

function FloatToAnsiStr(X: Single; Width: Integer = 0;
   Decimals: Integer = 0): AnsiString;
begin
   Str(X: Width: Decimals, Result);
end;

end.

Note that the overloaded FloatToAnsiStr function uses default Width and Decimal arguments (with a default value of 0). Also note that the Str function always uses the dot as decimal separator in the string result, and doesn’t consider the DecimalSeparator value. If you want to use the DecimalSeparator, you may want to change the functions as follows:

function FloatToAnsiStr(X: Double; Width: Integer = 0;
   Decimals: Integer = 0): AnsiString;
const
   Dot: AnsiChar = '.';
begin
   Str(X: Width: Decimals, Result);
   if DecimalSeparator <> '.' then
   begin
      Decimals := AnsiPos(Dot, Result);
      if Decimals > 0 then Result[Decimals] := AnsiChar(DecimalSeparator)
   end
end;

This will use the DecimalSeparator, narrowed back to AnsiChar (and I’m assuming nobody will use a Unicode Character which doesn’t “map” back to an AnsiChar as DecimalSeparator, but if you do, you could just stick to the normal FloatToStr anyway).

This tip is the 8th in a series of Unicode tips taken from my Delphi 2009 Development Essentials book published earlier this week on Lulu.com.