VC++互相转码GBK，unicode，utf8

windows平台下微软的库自带了一些api可用于几种编码格式间的互相转码，其实可以用一个iconv开源跨平台的转码库，那个方法更方便且统一。

使用前要引入头文件和命名空间

#include <iostream>
#include <string>
#include <fstream>
#include <windows.h>
using namespace std;

string GBKToUTF8(std::string& strGBK)
{
    string strOutUTF8 = "";
    WCHAR * str1;
    int n = MultiByteToWideChar(CP_ACP, 0, strGBK.c_str(), -1, NULL, 0);
    str1 = new WCHAR[n];
    MultiByteToWideChar(CP_ACP, 0, strGBK.c_str(), -1, str1, n);
    n = WideCharToMultiByte(CP_UTF8, 0, str1, -1, NULL, 0, NULL, NULL);
    char * str2 = new char[n];
    WideCharToMultiByte(CP_UTF8, 0, str1, -1, str2, n, NULL, NULL);
    strOutUTF8 = str2;
    delete[]str1;
    str1 = NULL;
    delete[]str2;
    str2 = NULL;
    return strOutUTF8;
}

 

string UTF8ToGBK(const std::string& strUTF8)
{
 int len = MultiByteToWideChar(CP_UTF8, 0, strUTF8.c_str(), -1, NULL, 0);
 unsigned short * wszGBK = new unsigned short[len + 1];
 memset(wszGBK, 0, len * 2 + 2);
 MultiByteToWideChar(CP_UTF8, 0, (LPCTSTR)strUTF8.c_str(), -1, wszGBK, len);

 len = WideCharToMultiByte(CP_ACP, 0, wszGBK, -1, NULL, 0, NULL, NULL);
 char *szGBK = new char[len + 1];
 memset(szGBK, 0, len + 1);
 WideCharToMultiByte(CP_ACP,0, wszGBK, -1, szGBK, len, NULL, NULL);
 //strUTF8 = szGBK;
 std::string strTemp(szGBK);
 delete[]szGBK;
 delete[]wszGBK;
 return strTemp;
}

 

void UnicodeToUTF8(wchar_t* strW, char szUtf8[])
 {
#ifdef _MSC_VER
     char* pElementText;
     int nTextLen;

     nTextLen =  WideCharToMultiByte(
         CP_UTF8,            // code page
         0,            // performance and mapping flags
         strW,    // wide-character string
         -1,          // number of chars in string.
         NULL,     // buffer for new string
         0,          // size of buffer
         NULL,     // default for unmappable chars
         NULL  // set when default char used
         );
     pElementText = new char[nTextLen+1];
     memset((void *)pElementText,0,sizeof(char)* (nTextLen+1));
     WideCharToMultiByte(
         CP_UTF8,            // code page
         0,            // performance and mapping flags
         strW,    // wide-character string
         -1,          // number of chars in string.
         pElementText,     // buffer for new string
         nTextLen,          // size of buffer
         NULL,     // default for unmappable chars
         NULL  // set when default char used
         );

     sprintf_s(szUtf8, nTextLen, "%s", pElementText);

     delete[] pElementText;
     return ;
#endif
 }

使用举例：

string test("源编码格式需要转成目标编码格式");
fstream output("test.txt"); //输出到文件
output << GBKToUTF8(test);

一般来说utf8用的比较多，推荐都转成utf8

http://blog.csdn.net/u012234115/article/details/42292035