cstring | 易学教程

Converting a C-style string to a C++ std::string

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问题 What is the best way to convert a C-style string to a C++ std::string ? In the past I've done it using stringstream s. Is there a better way? 回答1: C++ strings have a constructor that lets you construct a std::string directly from a C-style string: const char* myStr = "This is a C string!"; std::string myCppString = myStr; Or, alternatively: std::string myCppString = "This is a C string!"; As @TrevorHickey notes in the comments, be careful to make sure that the pointer you're initializing the

读取中文文件到CString

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　　 CString strFileName = _T("D:\\ai\\100.json"); CFile file; file.Open(strFileName, CFile::modeRead); INT sz = file.GetLength(); WCHAR *wBuf = new WCHAR[sz + 1]; char* buffer_src = new char[sz + 1]; file.Read(buffer_src, sz * sizeof(char)); buffer_src[sz] = '\0'; wBuf[sz] = '\0'; file.Close(); MultiByteToWideChar(CP_UTF8,0,buffer_src,-1,wBuf,sz + 1); CString strJson1(buffer_src); OutputDebugString(strJson1); CString strJson2(wBuf); // wBuf这里已经是中文的了 OutputDebugString(strJson2); //buffer_src转为wBuf一样的非乱码中文 WideCharToMultiByte(CP_ACP,0,wBuf,-1,buffer_src,sz + 1,0,0); CString strJson(buffer_src);

MFC常用类、成员函数、数组类、Cstring类、CTime类、CPoint类

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MFC数组类 CByteArray： CDWordArray： CPtrArray： CUIntArray： CWordArray： CStringArray：常用成员函数 1．int Add（ ARG_TYPE newElement ）; throw（ CMemoryException ）; 2．TYPE& ElementAt（ int nIndex ）; 3．void FreeExtra（）; 4．TYPE GetAt（ int nIndex ） const 5．int GetSize（） const; 6．int GetUpperBound（） const; 7．(1)void InsertAt（ int nIndex, ARG_TYPE newElement, int nCount = 1 ）; throw（ CMemoryException ）; (2)void InsertAt（ int nStartIndex, CArray* pNewArray ）; throw（ CMemoryException ）; 8．void RemoveAll（）; 9．void SetAt（ int nIndex, ARG_TYPE newElement ）; 10．void SetAtGrow（ int nIndex, ARG_TYPE newElement ）; throw

VC++ 字符串操作学习总结

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vc++中各种字符串(转载) http://www.cnblogs.com/tomin/archive/2008/12/28/1364097.html CString ,BSTR ,LPCTSTR之间关系和区别 CString是一个动态TCHAR数组，BSTR是一种专有格式的字符串（需要用系统提供的函数来操纵，LPCTSTR只是一个常量的TCHAR指针。 CString 是一个完全独立的类，动态的TCHAR数组，封装了 + 等操作符和字符串操作方法。 typedef OLECHAR FAR* BSTR; typedef const char * LPCTSTR; vc++中各种字符串的表示法首先char* 是指向ANSI字符数组的指针，其中每个字符占据8位（有效数据是除掉最高位的其他7位），这里保持了与传统的C,C++的兼容。 LP的含义是长指针(long pointer)。LPSTR是一个指向以‘\0’结尾的ANSI字符数组的指针，与char*可以互换使用，在 win32中较多地使用LPSTR。而LPCSTR中增加的‘C’的含义是“CONSTANT”（常量），表明这种数据类型的实例不能被使用它的API函数改变，除此之外，它与LPSTR是等同的。 1.LP表示长指针,在win16下有长指针(LP)和短指针(P)的区别,而在win32下是没有区别的,都是32位

Why do i first have to strcpy() before strcat()?

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Why does this code produce runtime issues: char stuff[100]; strcat(stuff,"hi "); strcat(stuff,"there"); but this doesn't? char stuff[100]; strcpy(stuff,"hi "); strcat(stuff,"there"); strcat will look for the null-terminator, interpret that as the end of the string, and append the new text there, overwriting the null-terminator in the process, and writing a new null-terminator at the end of the concatenation. char stuff[100]; // 'stuff' is uninitialized Where is the null terminator? stuff is uninitialized, so it might start with NUL, or it might not have NUL anywhere within it. In C++, you can

UTF-8, CString and CFile? (C++, MFC)

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问题 I'm currently working on a MFC program that specifically has to work with UTF-8. At some point, I have to write UTF-8 data into a file; to do that, I'm using CFiles and CStrings. When I get to write utf-8 (russian characters, to be more precise) data into a file, the output looks like Ðàñïå÷àòàíî: Ñèñòåìà Ïðîèçâîäñòâî and etc. This is assurely not utf-8. To read this data properly, I have to change my system settings; changing non ASCII characters to a russian encoding table does work, but

How to convert CString and ::std::string ::std::wstring to each other?

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CString is quite handy, while std::string is more compatible with STL container. I am using hash_map . However, hash_map does not support CString as key, so I want to convert CString into std::string . Writing a CString hash function seems to take a lot of time. CString -----> std::string How can I do this? std::string -----> CString: inline CString toCString(std::string const& str) { return CString(str.c_str()); } Am I right? EDIT: Here are more questions: How can I convert wstring , CString to each other? //wstring -> CString, std::wstring src; CString result(src.c_str()); //CString->wstring

What does _T stands for in a CString

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问题 What does the "T" represents in a string. For example _T("Hello").I have seen this in projects where unicode support is needed.What it actually tells the processor 回答1: _T stands for “text”. It will turn your literal into a Unicode wide character literal if and only if you are compiling your sources with Unicode support. See http://msdn.microsoft.com/en-us/library/c426s321.aspx. 回答2: From MSDN: Use the _T macro to code literal strings generically, so they compile as Unicode strings under

Proper way to copy C-strings

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问题 Is there an easy way to copy C-strings? I have const char *stringA , and I want char *stringB to take the value (note that stringB is not const ). I tried stringB=(char*) stringA , but that makes stringB still point to the same memory location, so when stringA later changes, stringB does too. I've also tried strcpy(stringB,stringA) , but it seems that if stringB wasn't initialized to a large enough array, there's a segfault. I'm not super experienced with C-strings though, am I missing

FJUT2019暑假第二次周赛题解

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A 服务器维护题目大意：　　给出时间段[S,E]，这段时间需要人维护服务器，给出n个小时间段[ai,bi]，代表每个人会维护的时间段，每个人维护这段时间有一个花费，现在问题就是维护服务器[S,E]这段时间，需要最小花费是多少，就是用n个小时间段[ai,bi]，覆盖满[S,E]这段时间并且所用的花费最少。解题思路：　　解法一：最短路径，这是我一开始想到的用的算法，S到E需要使用最小花费，并且还给出每一小段的路程和花费，感觉就像最短路径裸题吖，但是这题问题在于如何建图，如果你使用常规方法建图是不可行的，因为最短路径是覆盖边，而这题给出的是需要覆盖点，假设[2,4] 我们需要覆盖点2，3，4三个点，而一般最短路径建图[2,4]是覆盖2->3，3->4两条边，我们就少一个覆盖的权，所以我们就把终点+1，[2,4]转换成[2,5]，2->3，3->4，4->5，对应了2，3，4三个点，在建图时，假如给定区间[2,3] 覆盖点2，3对应边为2->3，3->4，我们就建一条从2->4的边，对于给定[ai,bi]建一条ai->bi+1的边。还有一个问题就是关于区间重复的覆盖，例如区间[2,5]和区间[3,6]，可以覆盖区间[2,6]，如果只按照上面建图是无法连通[2,6]的，所以我们需要给每一个点加一个反向边，就是从点i+1 ->点i且权值为0，这样当通过2-

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