Convert Hexadecimal to Integer

FUNCTION HexToInt(S: STRING): LongInt;
CONST
   DecDigits: SET OF '0'..'9' = ['0'..'9'];
   HexVals: ARRAY[0..$F] OF Integer = (0, 1, 2, 3, 4, 5, 6, 7, 8, 9,
      $A, $B, $C, $D, $E, $F);
   UpCaseHexLetters: SET OF 'A'..'F' = ['A'..'F'];
   LowCaseHexLetters: SET OF 'a'..'f' = ['a'..'f'];
   varv: LongInt;
   i: integer; LookUpIndex: integer;
BEGIN
   IF length(S) <= 8 THEN
   BEGIN
      v := 0;
      FOR i := 1 TO length(S) DO
      BEGIN
{$R-}
         v := v SHL 4;
{$R+}
         IF S[i] IN DecDigits THEN
         BEGIN
            LookUpIndex := Ord(S[i]) - Ord('0'); END
         ELSE
         BEGIN
            IF S[i] IN UpCaseHexLetters THEN
            BEGIN
               LookUpIndex := Ord(S[i]) - Ord('A') + $A;
            END
            ELSE
            BEGIN
               IF S[i] IN LowCaseHexLetters THEN
               BEGIN
                  LookUpIndex := Ord(S[i]) - Ord('a') + $A;
               END ELSE BEGIN LookUpIndex := 0;
               END;
            END;
         END;
         v := v OR HexVals[LookUpIndex];
      END;
      result := v;
   END
   ELSE
   BEGIN
      result := 0;
   END;
END;

Conversions between units of measurement

You must use the units
ConvUtils and StdConvs

Convert (value: Double; FromUnit, ToUnit: TConvType): Double;

Example:

Convert inch to centimeters

VAR inch, cnetimeters: Double;
BEGIN
   inch: = 21;
   Centimeters: Convert = (inch, auSquareInches, auSquareCentimeters);
   Memo.Lines.Add(Format('%8.4f inch of area = %8.4f centimeters of area ', [inch, centimeters]));

Convert Decimal to Roman Number

FUNCTION DecToRoman(Decimal: LongInt): STRING;
CONST Numbers: ARRAY[1..13] OF Integer = (1, 4, 5, 9, 10, 40, 50, 90, 100, 400, 500, 900, 1000);
   Roman: ARRAY[1..13] OF STRING = ('I', 'IV', 'V', 'IX', 'X', 'XL', 'L', 'XC', 'C', 'CD', 'D', 'CM', 'M');
VAR
   i: Integer;
BEGIN
   Result := '';
   FOR i := 13 DOWNTO 1 DO
      WHILE (Decimal >= Numbers[i]) DO
      BEGIN
         Decimal := Decimal - Numbers[i];
         Result := Result + Roman[i];
      END;
END;

Convert Integer to Binary

FUNCTION IntToBin(value, digits: integer): STRING;
VAR
   resultado: STRING;
   i: integer;
BEGIN
   IF digitos > 32 THEN
      digitos := 32;
   Resultado := '';
   i := 0;
   WHILE i < digitos DO
   BEGIN
      IF ((1 SHL i) AND valor) > 0 THEN
         Resultado := '1' + resultado
      ELSE
         Resultado := '0' + resultado;
      inc(i);
   END;
   Result := resultado;
END;

Other function

FUNCTION IntToBin(Value: LongInt; Size: Integer): STRING;
   VAR
      i: Integer;
   BEGIN
      Result := '';
      FOR i := Size - 1 DOWNTO 0 DO
         Result := Result + Chr(48 + Integer((Value AND (1 SHL i)) <> 0));
   END;

Converting between decimal, binary, and hexadecimal representation

USES
   StrUtils, SysUtils;

FUNCTION DecToBin(N: int64): STRING;
VAR
   i: integer;
   neg: boolean;
BEGIN
   IF N = 0 THEN BEGIN
      result := ’0’;
      exit
   END;
   SetLength(result, SizeOf(N) * 8);
   neg := N < 0;
   9
      N := Abs(N);
   i := 1;
   WHILE N <> 0 DO BEGIN
      IF N AND 1 = 1 THEN
         result[i] := ’1’
      ELSE
         result[i] := ’0’;
      N := N SHR 1;
      Inc(i);
   END;
   IF neg THEN BEGIN
      result[i] := ’’;
      Inc(i);
   END;
   Delete(result, i, length(result));
   result := ReverseString(result);
END;

FUNCTION DecToHex(N: int64): STRING;
BEGIN
   IF N < 0 THEN
      result := ’’
         + Format(’%0x’, [Abs(N)])
   ELSE
      result := Format(’%0x’, [N]);
END;