获取后缀

方法1：

char path[] = "D:\\bc.xlsx";

string strPath = path;

string suffix_str = strPath.substr(strPath.find_last_of('.') );//获取后缀

方法2：

char path[] = "D:\\bc.xlsx";

char path_buffer[_MAX_PATH];
char drive[_MAX_DRIVE];
char dir[_MAX_DIR];
char fname[_MAX_FNAME];
char ext[_MAX_EXT];

_splitpath(path, drive, dir, fname, ext);