[轉貼]10進位數轉任意整數N進位與反轉

示範例子至36進位：(含BCB與Delphi版本)

//===== BCB version -------------------------------------------------

AnsiString digits="0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"; // 36 進位

AnsiString DecimalToN(int value, int N, int withZeros=0)
// value:欲轉換的數值； N:欲轉換的進位制；
// withZeros: 總顯示位數，不足前方補零；內定值為0，則依實際位數顯示。
{ AnsiString result="";
   
    if ( N<=0 ) return result;
    if ( value==0 ) result="0";
    else
    { while( value>0 )
        { result = (AnsiString) digits[1 + value%N] + result;
        value /= N;
        }
    }
    while ( result.Length()    result = "0" + result;
    return (result);
}

int NToDecimal(AnsiString valString, int N)
{ int result=0, index=1;

    while( index<=valString.Length() )
    { result = result*N + ( digits.AnsiPos(valString[index]) -1 );
        index++;
    }
    return (result);
}

void __fastcall TForm1::Button1Click(TObject *Sender)
{ AnsiString value;

    value = DecimalToN(5438, 16, 5);
    ShowMessage(value);

    ShowMessage(IntToStr(NToDecimal(value, 16)));
}

//===== Delphi version -------------------------------------------------

const digits :string ='0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ'; // 36 進位

function DecimalToN(value, N :integer; withZeros :integer =0) :string;
begin
    result := '';
    if ( N<=0 ) then exit;
    if ( value=0 ) then
    result:='0'
    else
    begin
        while( value>0 ) do
        begin
        result := digits[1 + value mod N] + result;
        value := value div N;
        end
    end;
    while ( Length(result)    result := '0' + result;
end;

function NToDecimal(valString :string; N :integer) : integer;
var
    index :integer;
begin
    result := 0;
    index := 1;
    while( index<=Length(valString) ) do
    begin
        result := result*N + ( AnsiPos(valString[index], digits) -1 );
        index := index + 1;;
    end
end;

procedure TForm1.Button1Click(Sender: TObject);
var
    value : string;
begin
    value := DecimalToN(5438, 16, 5);
    ShowMessage(value);

    ShowMessage(IntToStr(NToDecimal(value, 16)));
end;




RichTop 敬上

轉貼至:http://delphi.ktop.com.tw/board.php?cid=31&fid=79&tid=54631

Delphi有部份程式內容裡截段, 修正如下

//10進位數轉任意整數N進位
function fn_DecimalToN(Value, N :integer; withZeros :integer =0) :string;
begin
  result := '';
  if ( N<=0 ) then
    exit;
  if ( Value=0 ) then
    result:='0'
  else
  begin
    while( value>0 ) do
    begin
      result := digits[1 + value mod N] + result;
      value := value div N;
    end
  end;
  while (Length(result) < withZeros) do
    result := '0' + result;
end;

//10進位數轉任意整數N進位(反轉)
function fn_NToDecimal(valString :string; N :integer) : integer;
var
    index :integer;
begin
  result := 0;
  index := 1;
  while(index <= Length(valString) ) do
  begin
    result := result*N + ( AnsiPos(valString[index], digits) -1 );
    index := index + 1;;
  end;
end;