格式化输入文件大小

string FormatFileSize(unsigned int iFileSize) { char buff[100]; memset(buff , 0 , sizeof(buff)); if (iFileSize >= 1073741824) { snprintf(buff , sizeof(buff)-1 , "%.2fG" , iFileSize / 1073741824.0); } else if (iFileSize >= 1048576) { snprintf(buff , sizeof(buff)-1 , "%.2fM" , iFileSize / 1048576.0); } else if (iFileSize >= 1024) { snprintf(buff , sizeof(buff)-1 , "%.2fK" , iFileSize / 1024.0); } else { snprintf(buff , sizeof(buff)-1 , "%dB" , iFileSize); } return buff; }