VC++ 中實現進制2進制，10進制，16進制的相互轉換

下面是一個圖例表示轉換過程使用的函數

                                        BinToDec                 CString::Format
                               2 --------------------------> 10 ---------------------------> 16
                               2 <-------------------------- 10 <--------------------------- 16
                                        DecToBin                        strtoul                        

1. 2 進制 -----> 10 進制

CString BinToDec(CString strBin)
{
    CString strDec;
    long nDec = 0, nLen;
    int i, j, k;
    
    nLen = strBin.GetLength();
    for (i=0; i<nLen; i++)
    {
        if ( strBin[nLen-i-1] == '0' )
            continue;
        else
        {
            k = 1;
            for(j=0; j<i; j++)
                k = k * 2;
            nDec += k;
        }        
    }
 
    strDec.Format("%ld", nDec);
 
    return strDec;
}

2. 10 進制 -----> 2 進制

CString DecToBin(CString strDec)
{
    int nDec = atoi(strDec);
    int nYushu, nShang;
    CString strBin = _T(""), strTemp;
    TCHAR buf[2];
    BOOL bContinue = TRUE;
 
    while ( bContinue )
    {
        nYushu = nDec % 2;
        nShang = nDec / 2;
        sprintf(buf, "%d", nYushu);
        strTemp = strBin;
        strBin.Format("%s%s", buf, strTemp);
        nDec = nShang;
        if ( nShang == 0 )
            bContinue = FALSE;
    }
    
    int nTemp = strBin.GetLength()%4;
    switch(nTemp) 
    {
    case 1:
        strTemp.Format(_T("000%s"), strBin);
        strBin = strTemp;
        break;
    case 2:
        strTemp.Format(_T("00%s"), strBin);
        strBin = strTemp;
        break; 
    case 3:
        strTemp.Format(_T("0%s"), strBin);
        strBin = strTemp;
        break;
    default:
        break;
    }
 
    return strBin;
}

3. 2進制 -----> 16進制

   2進制先轉換為10進制，再轉換為16進制

    CString strDec, strBin, strHex;
    strBin = _T("1110");
    strDec = BinToDec(strBin);
    int nDec;
    nDec = atol(strDec);
    strHex.Format(_T("%x"), nDec);  

4. 10 進制 -----> 16 進制

    int nDec = 10;
    CString str;
    str.Fomat(_T("%x"), nDec);

5. 16 進制 -----> 10 進制

    CString strDec, strHex;
    strHex = _T("af");
    DWord dwHex = strtoul(strHex, NULL, 16);
    strDec.Format(_T("%ld"), dwHex);

6. 16 進制 -----> 2 進制

    16進制先轉換為10進制，再轉換為2進制
  
    CString strDec, strBin, strHex;
    strHex = _T("af");
    DWord dwHex = strtoul(strHex, NULL, 16);
    strDec.Format(_T("%ld"), dwHex);
    strBin = DecToBin(strDec);

只是簡單寫了一下，沒有考慮效率問題。