可變長字串以及數字與字串的互轉

本文來自http://blog.csdn.net/hellogv/

//----------------------------------------------------------------------------------------------------------//使用方法：//先用string類型處理字串，當要傳遞參數時(參數為LPCWSTR)，才把string to wstring ,然後再傳遞wstring.c_str();//-----------------------------------------------------------------------------------------------------------#include <windows.h>#include <atlbase.h>#include <sstream>#include <string>using namespace std;    string Int2Str(int i)    {        ostringstream os;        os << i;        return os.str();    };    int Str2Int(string str)    {        return atoi(str.c_str());    }    //------wstring to string    string ws2s(wstring& inputws)    {        LPCWSTR pwszSrc=inputws.c_str();        int nLen = WideCharToMultiByte(CP_ACP, 0, pwszSrc, -1, NULL, 0, NULL, NULL);        if (nLen<= 0) return std::string("");        char* pszDst = new char[nLen];        if (NULL == pszDst) return std::string("");        WideCharToMultiByte(CP_ACP, 0, pwszSrc, -1, pszDst, nLen, NULL, NULL);        pszDst[nLen -1] = 0;        std::string strTemp(pszDst);        delete [] pszDst;        return strTemp;    }    //------string to wstring    std::wstring s2ws(const string& s)    {        LPCSTR pszSrc=s.c_str();        int nLen=s.size();        int nSize = MultiByteToWideChar(CP_ACP, 0, (LPCSTR)pszSrc, nLen, 0, 0);        if(nSize <= 0) return NULL;        WCHAR *pwszDst = new WCHAR[nSize+1];        if( NULL == pwszDst) return NULL;        MultiByteToWideChar(CP_ACP, 0,(LPCSTR)pszSrc, nLen, pwszDst, nSize);        pwszDst[nSize] = 0;        if( pwszDst[0] == 0xFEFF) // skip Oxfeff            for(int i = 0; i < nSize; i ++)                pwszDst[i] = pwszDst[i+1];        wstring wcharString(pwszDst);        delete pwszDst;        return wcharString;   };