关于c++中utf8和gbk编码方式的转换

GBK转utf8如下：

string GBKToUTF8(const 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;  
}  

utf8转GBK如下：

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;  
}  

C++头文件包含文件：

#include <iostream> 
#include <string> 
#include <fstream> 
#include <windows.h>