一、完全用API完成:..uses Windows;
function IntToStr(I: integer): string;
begin
   Str(I, Result);
end;

function StrToInt(S: string): integer;
begin
Val(S, Result, Result);
end;

function HexToInt(Const HexValue: String) : Integer;
begin
   Val(‘$‘+HexValue, Result, Result);
end;

function IntToHex(Const Value: Integer): string;
const
   HexChars: array[0..15] of Char = ‘0123456789ABCDEF‘;
var
   iTemp: Integer;
   i: Integer;
begin
   Result := ‘‘;
   i := 0;
   while i<4 do
   begin
     case i of
       0: iTemp := Value shr 24 and $FF;
       1: iTemp := Value shr 16 and $FF;
       2: iTemp := Value shr 8 and $FF;
       3: iTemp := Value and $FF;
     end;
     Result := Result + HexChars[iTemp div 16];
     Result := Result + HexChars[iTemp mod 16];
     Inc(i);
   end;
end;

function LowerCase(const S: string): String;
begin
   Result:=CharLower(Pchar(S));
end;

function UpperCase(const S: string): String;
begin
   Result:=CharUpper(Pchar(S));
end;

二、函數(shù)實(shí)現(xiàn)

//十進(jìn)制 to 二進(jìn)制
function IntToBin(Value: LongInt;Size: Integer): String;
var
i: Integer;
begin
Result:=‘‘;
for i:=Size-1 downto 0 do begin
    if Value and (1 shl i)<>0 then begin
       Result:=Result+‘1‘;
end else begin
       Result:=Result+‘0‘;
end;
end;
end;

//二進(jìn)制 to 十進(jìn)制

function BintoInt(Value:   String):   LongInt;
var
      i,Size:   Integer;
begin
      Result:=0;
      Size:=Length(Value);
      for   i:=Size   downto   1   do
      begin
          if   Copy(Value,i,1)=‘1‘   then
              Result:=Result+(1   shl   (Size-i));
      end;
end;

function floatBintoInt(Value:   String):   real;
var
      i,Size:   Integer;
begin
      Result:=0;
      Size:=Length(Value);
      for   i:=Size   downto   1   do
      begin
          if   Copy(Value,i,1)=‘1‘   then
              Result:=Result+1/(1   shl i);
      end;
end;

//十六進(jìn)制 to 二進(jìn)制

function HextoBinary(Hex:string):string;
const
    BOX: array [0..15] of string =
         (‘0000‘,‘0001‘,‘0010‘,‘0011‘,
          ‘0100‘,‘0101‘,‘0110‘,‘0111‘,
          ‘1000‘,‘1001‘,‘1010‘,‘1011‘,
          ‘1100‘,‘1101‘,‘1110‘,‘1111‘);
var
    i:integer;
begin
    for i:=Length(Hex) downto 1 do
        Result:=BOX[StrToInt(‘$‘+Hex[i])]+Result;
end;

//十六進(jìn)制 to 十進(jìn)制 浮點(diǎn)型
function HextoFloat(s:string):real;
var b,temp:string;
    e:integer;
    f:real;
begin
b:=HextoBinary(s);
temp := copy(b,2,8);
e:=BintoInt(temp)-127;
temp := copy(b,10,23);
f := 1+floatBintoInt(temp);
if(copy(b,1,1)=‘0‘)then
    result := power(2,e)*f
else
    result :=-power(2,e)*f;
end;