字符串转为时间。时间差，几天，几小时，几分

const char* pszEndTime =“2021-09-10 12:00:00 struct tm end = { 0 }; sscanf_s(pszEndTime,"%d-%d-%d %d:%d:%d", &end.tm_year, &end.tm_mon, &end.tm_mday ,