350.zip_foxpro_其他数据库_数据库系统下载-pudn.com

<html><head><meta http-equiv=Content-Type content=text/html; charset=gb2312><title>g. 二/八/十/十六进制转换函数</title></head><body bgcolor=#F4ECDB>g. 二/八/十/十六进制转换函数夜来香Conversion Functions: Dec,Hex,Binary,Oct Back and Forth     Here are a few conversion functions. Some of which have already been convered in threads, but I thought I would put them in an FAQ for easier reference.     1 Hex>Decimal      Convert Hexadecimal values to Decimal     2 Decimal>Hex      Convert Decimal values to Hexadecimal     3 So. What if we need bigger? Different base?     4 Dec2BasX      Convert Decimal values to any base from binary to hex (216)     5 Binary>Decimal      Convert 1's and 0's to whole number     6 Binary>Hex      Convert 1's and 0's to hex number     7 Another Hex>Decimal      For grins, here's a manual hex>dec conversion function     8 Float>Binary>BCD      Take a float (e.g. 123.45) and convert it to binary string which can then be converted to hex bcd using bin2hex.     9 .Decimal>Binary      Convert floating point fraction to binary string     10 Binary>Hexadecimal      Convert binary string to bcd hex in groups of 4     11 BCD>Hexidecimal>Binary      Convert hex bcd number to binary representation of bcd number     12 Binary>Float      Converts binary to floating point decimal number, whole portion and fraction.     13 Binary>Decimal      Convert binary string to whole number     14 Binary>.Decimal      Convert binary string to decimal fraction     15 Tie 'em together      Let's do some converting now     16 Complete procedure file CVT.PRG      This is a complete listing of the functions with no tutorials, so it should compile error free if you cut and paste to a procedure file.     17 Form code to demo conversions      This is a demo form. Input a number and hit Enter or click the 'Convert' button. It will do the converting, then convert it back for comparison. Not that you need the aforementioned procedure file laying around so the program can grab it.     First, let's look at the built in ones.     1 Hex>Decimal     Natively, VFP can do hex to decimal conversion like this:     ?0xffff     or     STORE 0xffff TO nVar     And so on. The result is an integer value, 65535.     2 Decimal>Hex     VFP can also convert decimal to hex:     ?Transform(65535, '@0x')     or     STORE Transform(65535, '@0x') TO cHexStr     Notice that the return value is character, but you get a hex representation of 65535 as 0x0000FFFF.     Note: The largest hex value that can be returned by this method is 4294967295, or 0xFFFFFFFF     3 So. What if we need bigger? Different base?     Following are a couple functions I wrote for previous apps. One function that will take a whole number in the range of 09007199254740992 and convert it to any base, as long as it is base 2 to 16. That includes binary, octal, or any useless base in between.     The biggest number it can handle is 9007199254740992, as VFP docs point out, that is the biggest number VFP can handle.     4 Dec2BasX     *..............................................................................     * Function: DEC2BASX     * Purpose: Convert whole number 0?, to base 216     *     * Parameters: nTempNum number to convert (09007199254740992)     * base base to convert to i.e., 2 4 8 16...     * returns: string     * Usage: cresult=Dec2BasX(nParm1, nParm2)     * STORE Dec2BasX(255, 16) TO cMyString &&... cMyString contains 'ff'     *..............................................................................     FUNCTION dec2basx     PARAMETERS nTempNum, nNewBase     STORE 0 TO nWorkVal,;      remainder,;      dividend,;      nextnum,;      digit     nWorkVal = nTempNum     ret_str = ''     DO WHILE .T.      digit = MOD(nWorkVal, nNewBase)      dividend = nWorkVal / nNewBase      nWorkVal = INT(dividend)      DO CASE      CASE digit = 10      ret_str = 'a' + ret_str      CASE digit = 11      ret_str = 'b' + ret_str      CASE digit = 12      ret_str = 'c' + ret_str      CASE digit = 13      ret_str = 'd' + ret_str      CASE digit = 14      ret_str = 'e' + ret_str      CASE digit = 15      ret_str = 'f' + ret_str      OTHERWISE      ret_str = LTRIM(STR(digit)) + ret_str      ENDCASE      IF nWorkVal = 0      EXIT      ENDIF ( nWorkVal = 0 )     ENDDO ( .T. )     RETURN ret_str     *: eof dec2basx     5 Binary>Decimal     Now, we want to convert binary to decimal. This function will take a binary string between '0' and     '11111111111111111111111111111111111111111111111111111'     (53 1's, or 9007199254740991) and convert it to decimal.     *..................................................................     * Function: bin2dec     * Purpose: convert binary string to decimal number     * Parameters: pbinnum string to convert i.e.,     * '0' '11111111111111111111111111111111111111111111111111111'     * '0' (53 1's)     * returns: integer data type     * Usage: nresult = Bin2Dec(cParm1)     * STORE Bin2Dec('11111111') TO nMyNum &&... nMyNum contains 255     *