C++文字列間変換-Unicode文字セット

この文書では、Unicode文字セットの下の文字列間および文字列と数値間の変換について説明します.1.string、char*およびconst char*<1>string->char*

char *ctr = new char[str.length()+1];
    strcpy(ctr,str.c_str());
    delete[]ctr; //        

<2>string->const char*

    string str("good");
    const char *p = str.c_str();//   const char*

<3>char*->string

    char *ctr = "good";
    string str(ctr);
    // 
    string str2 = ctr;

<4>char*->const char*

    char *ctr = "good";
    const char *ctr2 = ctr;

<5>const char*->string

    const char *ctr = "good";
    string str(ctr);

<6>const char*->char*

    const char *ctr = "good";
    char *ctr2= new char[strlen(ctr)+1] ;
    strcpy(ctr2, ctr);
    delete[]ctr; //        
//  char[]   char *   ，        

2.char*stringとCString
<1>char*->CString

    char *p = "good";
    CString cstr = p;
    // 
    char *p = "good";
    CString cstr;
    cstr.Format("%s",p);

<2>string->CString

    string str = "good";
    CString cstr = str.c_str();
    // 
    string str = "good";
    CString cstr;
    cstr.Format("%s",str.c_str());

<3>CString->char*

    CString str = _T("good");
    char *chr=new char[cstr.GetLength()+1];
    WideCharToMultiByte(CP_ACP,0,str.AllocSysString(),-1,chr,cstr.GetLength()+1,NULL,NULL);
    // 
    char *p;
    int nCharLen;
    nCharLen = WideCharToMultiByte(CP_ACP, 0,str.AllocSysString(), -1, NULL, 0, NULL, NULL);
    p = new char [nCharLen + 1];
    memset(p,0,nCharLen + 1);
    WideCharToMultiByte(CP_ACP, 0, str.AllocSysString(), -1, p, nCharLen + 1, NULL, NULL);

<4>CString->string

    CString cstr = "good";
    string str = cstr;
    // 
    string str = CStringA(cstr);
    // 
    char *chr=new char[cstr.GetLength()+1];
  WideCharToMultiByte(CP_ACP,0,cstr.AllocSysString(),-1,chr,cstr.GetLength()+1,NULL,NULL);
    string str=chr;

3.数字と文字列の変換1.doubleとstring

<1>double->string
    char temp[20];
    double a = 0.631;
    sprintf_s(temp, "%.2f", a);//  2   
    string str =temp;

<2>string->double

    string a = "0.631";
    double b = atof(a.c_str());

2.doubleとchar*<1>double->char*

    char temp[20];
    double a = 0.631;
    sprintf_s(temp, "%.2f", a);//  2   
    char *p = temp;

<2>char*->double

    char *a = "0.631";
    double b = atof(a);
//     int ，  “%f”->"%d"、atof->atoi

3.doubleとCString<1>double->CString

    double a = 0.631;
    CString cstr;
    cstr.Format("%.2f",a);

<2>CString->double

    CString cstr = "0.631";
    double a = atof(cstr);  
//     int ，  “%f”->"%d"、atof->atoi

4その他の文字列間の変換<1>LPCWSTR回転char*

/***********************************************************************
        ：ConvertLPWSTRToChar
        ：     ，LPCWSTR   char*
        ：
            lpwszStrIn  ：LPCWSTR   

       ：     
        ：pzh
        ：2016.3.4
      ：
***********************************************************************/
char*  ConvertLPWSTRToChar (LPWSTR lpwszStrIn)  
{  
    LPSTR pszOut = NULL;  
    if (lpwszStrIn != NULL)  
    {  
        int nInputStrLen = wcslen (lpwszStrIn);  

        // Double NULL Termination  
        int nOutputStrLen = WideCharToMultiByte (CP_ACP, 0, lpwszStrIn, nInputStrLen, NULL, 0, 0, 0) + 2;  
        pszOut = new char [nOutputStrLen];  

        if (pszOut)  
        {  
            memset (pszOut, 0x00, nOutputStrLen);  
            WideCharToMultiByte(CP_ACP, 0, lpwszStrIn, nInputStrLen, pszOut, nOutputStrLen, 0, 0);  
        }  
    }  
    return pszOut;  
}  

<2>string回転LPWSTRTまたはWCHAR

string strTemp = "113";
WCHAR wcharTemp[256];  //string   LPWSTRT
MultiByteToWideChar(CP_ACP,0,strTemp.c_str(),-1,wcharTemp,sizeof(wcharTemp)/sizeof(wcharTemp[0]));