CString::ReverseFind()与CString ::Find()的区别？

lunpinghh 2003-08-19 07:49:07

为什么ReverseFind()也是从左往右数，那与FIND的区别是什么？

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闻缺陷则喜何志丹 2003-08-19

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都是找第一个'b'
一个从开始找
一个从后面找

闻缺陷则喜何志丹 2003-08-19

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CString str = "abcdb";
int x1 = str.Find('b');
int x2 = str.ReverseFind('b');
x2 = 4;
x1 = 1;

yakai 2003-08-19

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返回的地址都是从左向右数的，但开始时是从右向左的，你放两个相同的子串，两个函数返回的值是不同的你就知道了

joy0861 2003-08-19

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不是ReverseFind()是反向查找，返回的是与搜索字符相同的最近一个字符的位置，而这个位置的计算是从左往右的。

HongHuer 2003-08-19

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实际测试一下就知道了啊。

// ============================================================================= // FILE: StdString.h // AUTHOR: Joe O'Leary (with outside help noted in comments) // // If you find any bugs in this code, please let me know: // // jmoleary@earthlink.net // http://www.joeo.net/stdstring.htm (a bit outdated) // // The latest version of this code should always be available at the // following link: // // http://www.joeo.net/code/StdString.zip (Dec 6, 2003) // // // REMARKS: // This header file declares the CStdStr template. This template derives // the Standard C++ Library basic_string<> template and add to it the // the following conveniences: // - The full MFC CString set of functions (including implicit cast) // - writing to/reading from COM IStream interfaces // - Functional objects for use in STL algorithms // // From this template, we intstantiate two classes: CStdStringA and // CStdStringW. The name "CStdString" is just a #define of one of these, // based upone the UNICODE macro setting // // This header also declares our own version of the MFC/ATL UNICODE-MBCS // conversion macros. Our version looks exactly like the Microsoft's to // facilitate portability. // // NOTE: // If you you use this in an MFC or ATL build, you should include either // afx.h or atlbase.h first, as appropriate. // // PEOPLE WHO HAVE CONTRIBUTED TO THIS CLASS: // // Several people have helped me iron out problems and othewise improve // this class. OK, this is a long list but in my own defense, this code // has undergone two major rewrites. Many of the improvements became // necessary after I rewrote the code as a template. Others helped me // improve the CString facade. // // Anyway, these people are (in chronological order): // // - Pete the Plumber (???) // - Julian Selman // - Chris (of Melbsys) // - Dave Plummer // - John C Sipos // - Chris Sells // - Nigel Nunn // - Fan Xia // - Matthew Williams // - Carl Engman // - Mark Zeren // - Craig Watson // - Rich Zuris // - Karim Ratib // - Chris Conti // - Baptiste Lepilleur // - Greg Pickles // - Jim Cline // - Jeff Kohn // - Todd Heckel // - Ullrich Poll?hne // - Joe Vitaterna // - Joe Woodbury // - Aaron (no last name) // - Joldakowski (???) // - Scott Hathaway // - Eric Nitzche // - Pablo Presedo // - Farrokh Nejadlotfi // - Jason Mills // - Igor Kholodov // - Mike Crusader // - John James // - Wang Haifeng // - Tim Dowty // - Arnt Witteveen // - Glen Maynard // - Paul DeMarco // - Bagira (full name?) // - Ronny Schulz // - Jakko Van Hunen // - Charles Godwin // - Henk Demper // - Greg Marr // - Bill Carducci // - Brian Groose // - MKingman // - Don Beusee // // REVISION HISTORY // // 2005-JAN-10 - Thanks to Don Beusee for pointing out the danger in mapping // length-checked formatting functions to non-length-checked // CRT equivalents. Also thanks to him for motivating me to // optimize my implementation of Replace() // // 2004-APR-22 - A big, big thank you to "MKingman" (whoever you are) for // finally spotting a silly little error in StdCodeCvt that // has been causing me (and users of CStdString) problems for // years in some relatively rare conversions. I had reversed // two length arguments. // // 2003-NOV-24 - Thanks to a bunch of people for helping me clean up many // compiler warnings (and yes, even a couple of actual compiler // errors). These include Henk Demper for figuring out how // to make the Intellisense work on with CStdString on VC6, // something I was never able to do. Greg Marr pointed out // a compiler warning about an unreferenced symbol and a // problem with my version of Load in MFC builds. Bill // Carducci took a lot of time with me to help me figure out // why some implementations of the Standard C++ Library were // returning error codes for apparently successful conversions // between ASCII and UNICODE. Finally thanks to Brian Groose // for helping me fix compiler signed unsigned warnings in // several functions. // // 2003-JUL-10 - Thanks to Charles Godwin for making me realize my 'FmtArg' // fixes had inadvertently broken the DLL-export code (which is // normally commented out. I had to move it up higher. Also // this helped me catch a bug in ssicoll that would prevent // compilation, otherwise. // // 2003-MAR-14 - Thanks to Jakko Van Hunen for pointing out a copy-and-paste // bug in one of the overloads of FmtArg. // // 2003-MAR-10 - Thanks to Ronny Schulz for (twice!) sending me some changes // to help CStdString build on SGI and for pointing out an // error in placement of my preprocessor macros for ssfmtmsg. // // 2002-NOV-26 - Thanks to Bagira for pointing out that my implementation of // SpanExcluding was not properly handling the case in which // the string did NOT contain any of the given characters // // 2002-OCT-21 - Many thanks to Paul DeMarco who was invaluable in helping me // get this code working with Borland's free compiler as well // as the Dev-C++ compiler (available free at SourceForge). // // 2002-SEP-13 - Thanks to Glen Maynard who helped me get rid of some loud // but harmless warnings that were showing up on g++. Glen // also pointed out that some pre-declarations of FmtArg<> // specializations were unnecessary (and no good on G++) // // 2002-JUN-26 - Thanks to Arnt Witteveen for pointing out that I was using // static_cast<> in a place in which I should have been using // reinterpret_cast<> (the ctor for unsigned char strings). // That's what happens when I don't unit-test properly! // Arnt also noticed that CString was silently correcting the // 'nCount' argument to Left() and Right() where CStdString was // not (and crashing if it was bad). That is also now fixed! // // 2002-FEB-25 - Thanks to Tim Dowty for pointing out (and giving me the fix // for) a conversion problem with non-ASCII MBCS characters. // CStdString is now used in my favorite commercial MP3 player! // // 2001-DEC-06 - Thanks to Wang Haifeng for spotting a problem in one of the // assignment operators (for _bstr_t) that would cause compiler // errors when refcounting protection was turned off. // // 2001-NOV-27 - Remove calls to operator!= which involve reverse_iterators // due to a conflict with the rel_ops operator!=. Thanks to // John James for pointing this out. // // 2001-OCT-29 - Added a minor range checking fix for the Mid function to // make it as forgiving as CString's version is. Thanks to // Igor Kholodov for noticing this. // - Added a specialization of std::swap for CStdString. Thanks // to Mike Crusader for suggesting this! It's commented out // because you're not supposed to inject your own code into the // 'std' namespace. But if you don't care about that, it's // there if you want it // - Thanks to Jason Mills for catching a case where CString was // more forgiving in the Delete() function than I was. // // 2001-JUN-06 - I was violating the Standard name lookup rules stated // in [14.6.2(3)]. None of the compilers I've tried so // far apparently caught this but HP-UX aCC 3.30 did. The // fix was to add 'this->' prefixes in many places. // Thanks to Farrokh Nejadlotfi for this! // // 2001-APR-27 - StreamLoad was calculating the number of BYTES in one // case, not characters. Thanks to Pablo Presedo for this. // // 2001-FEB-23 - Replace() had a bug which caused infinite loops if the // source string was empty. Fixed thanks to Eric Nitzsche. // // 2001-FEB-23 - Scott Hathaway was a huge help in providing me with the // ability to build CStdString on Sun Unix systems. He // sent me detailed build reports about what works and what // does not. If CStdString compiles on your Unix box, you // can thank Scott for it. // // 2000-DEC-29 - Joldakowski noticed one overload of Insert failed to do a // range check as CString's does. Now fixed -- thanks! // // 2000-NOV-07 - Aaron pointed out that I was calling static member // functions of char_traits via a temporary. This was not // technically wrong, but it was unnecessary and caused // problems for poor old buggy VC5. Thanks Aaron! // // 2000-JUL-11 - Joe Woodbury noted that the CString::Find docs don't match // what the CString::Find code really ends up doing. I was // trying to match the docs. Now I match the CString code // - Joe also caught me truncating strings for GetBuffer() calls // when the supplied length was less than the current length. // // 2000-MAY-25 - Better support for STLPORT's Standard library distribution // - Got rid of the NSP macro - it interfered with Koenig lookup // - Thanks to Joe Woodbury for catching a TrimLeft() bug that // I introduced in January. Empty strings were not getting // trimmed // // 2000-APR-17 - Thanks to Joe Vitaterna for pointing out that ReverseFind // is supposed to be a const function. // // 2000-MAR-07 - Thanks to Ullrich Poll?hne for catching a range bug in one // of the overloads of assign. // // 2000-FEB-01 - You can now use CStdString on the Mac with CodeWarrior! // Thanks to Todd Heckel for helping out with this. // // 2000-JAN-23 - Thanks to Jim Cline for pointing out how I could make the // Trim() function more efficient. // - Thanks to Jeff Kohn for prompting me to find and fix a typo // in one of the addition operators that takes _bstr_t. // - Got rid of the .CPP file - you only need StdString.h now! // // 1999-DEC-22 - Thanks to Greg Pickles for helping me identify a problem // with my implementation of CStdString::FormatV in which // resulting string might not be properly NULL terminated. // // 1999-DEC-06 - Chris Conti pointed yet another basic_string<> assignment // bug that MS has not fixed. CStdString did nothing to fix // it either but it does now! The bug was: create a string // longer than 31 characters, get a pointer to it (via c_str()) // and then assign that pointer to the original string object. // The resulting string would be empty. Not with CStdString! // // 1999-OCT-06 - BufferSet was erasing the string even when it was merely // supposed to shrink it. Fixed. Thanks to Chris Conti. // - Some of the Q172398 fixes were not checking for assignment- // to-self. Fixed. Thanks to Baptiste Lepilleur. // // 1999-AUG-20 - Improved Load() function to be more efficient by using // SizeOfResource(). Thanks to Rich Zuris for this. // - Corrected resource ID constructor, again thanks to Rich. // - Fixed a bug that occurred with UNICODE characters above // the first 255 ANSI ones. Thanks to Craig Watson. // - Added missing overloads of TrimLeft() and TrimRight(). // Thanks to Karim Ratib for pointing them out // // 1999-JUL-21 - Made all calls to GetBuf() with no args check length first. // // 1999-JUL-10 - Improved MFC/ATL independence of conversion macros // - Added SS_NO_REFCOUNT macro to allow you to disable any // reference-counting your basic_string<> impl. may do. // - Improved ReleaseBuffer() to be as forgiving as CString. // Thanks for Fan Xia for helping me find this and to // Matthew Williams for pointing it out directly. // // 1999-JUL-06 - Thanks to Nigel Nunn for catching a very sneaky bug in // ToLower/ToUpper. They should call GetBuf() instead of // data() in order to ensure the changed string buffer is not // reference-counted (in those implementations that refcount). // // 1999-JUL-01 - Added a true CString facade. Now you can use CStdString as // a drop-in replacement for CString. If you find this useful, // you can thank Chris Sells for finally convincing me to give // in and implement it. // - Changed operators << and >> (for MFC CArchive) to serialize // EXACTLY as CString's do. So now you can send a CString out // to a CArchive and later read it in as a CStdString. I have // no idea why you would want to do this but you can. // // 1999-JUN-21 - Changed the CStdString class into the CStdStr template. // - Fixed FormatV() to correctly decrement the loop counter. // This was harmless bug but a bug nevertheless. Thanks to // Chris (of Melbsys) for pointing it out // - Changed Format() to try a normal stack-based array before // using to _alloca(). // - Updated the text conversion macros to properly use code // pages and to fit in better in MFC/ATL builds. In other // words, I copied Microsoft's conversion stuff again. // - Added equivalents of CString::GetBuffer, GetBufferSetLength // - new sscpy() replacement of CStdString::CopyString() // - a Trim() function that combines TrimRight() and TrimLeft(). // // 1999-MAR-13 - Corrected the "NotSpace" functional object to use _istpace() // instead of _isspace() Thanks to Dave Plummer for this. // // 1999-FEB-26 - Removed errant line (left over from testing) that #defined // _MFC_VER. Thanks to John C Sipos for noticing this. // // 1999-FEB-03 - Fixed a bug in a rarely-used overload of operator+() that // caused infinite recursion and stack overflow // - Added member functions to simplify the process of // persisting CStdStrings to/from DCOM IStream interfaces // - Added functional objects (e.g. StdStringLessNoCase) that // allow CStdStrings to be used as keys STL map objects with // case-insensitive comparison // - Added array indexing operators (i.e. operator[]). I // originally assumed that these were unnecessary and would be // inherited from basic_string. However, without them, Visual // C++ complains about ambiguous overloads when you try to use // them. Thanks to Julian Selman to pointing this out. // // 1998-FEB-?? - Added overloads of assign() function to completely account // for Q172398 bug. Thanks to "Pete the Plumber" for this // // 1998-FEB-?? - Initial submission // // COPYRIGHT: // 2002 Joseph M. O'Leary. This code is 100% free. Use it anywhere you // want. Rewrite it, restructure it, whatever. If you can write software // that makes money off of it, good for you. I kinda like capitalism. // Please don't blame me if it causes your $30 billion dollar satellite // explode in orbit. If you redistribute it in any form, I'd appreciate it // if you would leave this notice here. // ============

struct FOLDERINFO { int fileLength; //记录文件长度 char fileName[128]; //记录文件名 char filePath[512] //记录文件路径 }; 这里需要说明一下,为什么文件名,文件路径不用CString定义,原因是这个结构体我们要发给对方的,但是由于CString长度是不丁长的,导致结构体长度不能确定,从而使程序出错. 下面就是发送方的代码,我已经省去了目录选择和遍历目录的代码: void CMyQQDlg::SendFiles() { CSocket sockClient; sockClient.Create(); //创建Socket CString ip; m_You_IP.GetWindowText(ip); //m_You_IP是IP控件的变量 sockClient.Connect(ip, 11024); // /////////////////////////////////////////////////////////////////// CString fileName; ///////////////////////这是发送方处理目录的代码,如果没有这段代码 fileName=m_fileName; //将只能发送根目录下的文件:) int a=fileName.Find(filepathone); if(a!=2) { fileName=fileName.Right(fileName.GetLength()-a-1); fileName="C:\\"+fileName; } //////////////////////////////////////////////////////////////////////////// CFile myFile; FOLDERINFO myFileInfo; if(!myFile.Open(m_fileName,CFile::modeRead|CFile::typeBinary))//m_fileName是遍历后得到的文件 return ; myFileInfo.fileLength=myFile.GetLength(); //得到文件大小 strcpy(myFileInfo.fileName,myFile.GetFileName()); //得到文件名称 strcpy(myFileInfo.filePath,m_fileName); sockClient.Send(&myFileInfo,sizeof(myFileInfo)); //发送文件信息 myFile.Seek(0,CFile::begin); char m_buf[SIZEFILE]={0}; //缓冲区 CString strError; int num=0; int temp=0; //开始发送 for(;;) { num=myFile.Read(m_buf, SIZEFILE); if(num==0) break; end=sockClient.Send(m_buf, num); temp+=end; } myFile.Close(); sockClient.Close(); return ; } 下面就是接收方的代码: int CMyQQDlg::SaveYouFiles(CSocket &recSo, SOCKADDR_IN &client) { CString fnames; CString filenamepath; static int filescount=0; CString strfileIp,strfileName,strfileLength; char filemes[512]={0};//存文件名字的 int fileLengths=0; FOLDERINFO myFileInfo; recSo.Receive(&myFileInfo,sizeof(FOLDERINFO)); fileLengths=myFileInfo.fileLength; strfileIp.Format(inet_ntoa(client.sin_addr)); strfileName.Format(myFileInfo.fileName); //得到文件名字 strfileLength.Format("%f",myFileInfo.fileLength/1024.0); filenamepath.Format(myFileInfo.filePath); //得到文件路径 int a=filenamepath.ReverseFind(_T('\\'));//这5行代码是用来得到一个例如:\AMD\Intel\ATI\ filenamepath=filenamepath.Left(a+1); //主要是用来建立目录 CString b=filenamepath; a=b.ReverseFind(_T(':')); b=b.Right(b.GetLength()-a-1); filenamepath="files"+b; //所有的文件都存在files文件夹下 CreateDirectory(filenamepath,NULL); //创建目录 strcpy(filemes,filenamepath+strfileName); char bufs[SIZEFILE]={0}; //缓冲SIZEFILE=1024 CFile fs(filemes,CFile::modeCreate|CFile::modeWrite); //存文件 int n=0; //接受的字节数 0表示结束 int temp=0; //开始接收 for(;;) { n=recSo.Receive(bufs,SIZEFILE); //接受 if(n==0) //0表示结束 break; //接受完毕 fs.Write(bufs,n); // fputs(bufs,fp); temp+=n; } fs.Close(); return 0; }

CString::ReverseFind int ReverseFind( TCHAR ch ) const; 返回值：参数： ch 要搜索的字符。说明：此成员函数在此CString对象中搜索与一个子串匹配的最后一个字符。此函数类似于运行时函数strrchr。 “最后一个字符”是指从左往右的最后一

Find()是从左往右查找；ReverseFind()是从右边往左查找，但是他们返回的地址都是从左往右数的。示例：[cpp] #include “stdafx.h” #include "afx.h" int main(int argc,char *argv){ CString str = "abcdabcd"; int a = str.Find('b'); printf("

此三个函数返回值均为整数int。 1、Find() 该函数从左侧0索引开始，查找第一个出现的字符位置，返回position。示例如下： 1 CString s( “abcd” ); 2 ASSERT( s.Find( ‘b’ ) == 1 ); 返回值：如果查到，返回以0索引起始的位置未查到，返回-1 2、FindOneOf() 给定一字符串，然后查找其中出现的第一个字符位置，示例如下： 1 CString s( “abcdef” ); 2 ASSERT( s.FindOneOf( “zb” ) ==

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