windows下std::string怎么读取utf-8字符

在Windows下使用std::string读取UTF-8字符可以使用以下方法：

1. 使用MultiByteToWideChar函数将UTF-8编码转换为Unicode编码。

#include <Windows.h>
#include <string>

std::string utf8_to_string(const char* utf8_string)
{
    int len = MultiByteToWideChar(CP_UTF8, 0, utf8_string, -1, NULL, 0);
    wchar_t* wstr = new wchar_t[len];
    MultiByteToWideChar(CP_UTF8, 0, utf8_string, -1, wstr, len);

    std::wstring wstring(wstr);
    delete[] wstr;

    return std::string(wstring.begin(), wstring.end());
}

2. 使用iconv库进行编码转换。

#include <iconv.h>
#include <string>

std::string utf8_to_string(const char* utf8_string)
{
    iconv_t conv = iconv_open("CP932", "UTF-8");
    if (conv == (iconv_t)-1) {
        // handle error
    }

    char* inbuf = const_cast<char*>(utf8_string);
    size_t inbytesleft = strlen(utf8_string);
    size_t outbytesleft = inbytesleft * 2;  // assuming worst case
    char* outbuf = new char[outbytesleft];

    char* inbufp = inbuf;
    char* outbufp = outbuf;
    iconv(conv, &inbuf, &inbytesleft, &outbuf, &outbytesleft);

    std::string result(outbufp, outbuf - outbufp);
    delete[] outbuf;

    iconv_close(conv);

    return result;
}