可变长字符串以及数字与字符串的互转

本文来自http://blog.csdn.net/hellogv/

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//----------------------------------------------------------------------------------------------------------

//使用方法：

//先用string类型处理字符串，当要传递参数时(参数为LPCWSTR)，才把string to wstring ,然后再传递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;

   

};