请问QT在声明全局变量的头文件中为什么显示map does not name a type,deque和stack也是这样
*^~^ 2020-07-07 11:13:13 #pragma once
#include<map>
#include<deque>
#include<stack>
#include"car.h"
#include<QString>
extern map<QString,int> mp;
extern deque<car> park;
extern deque<car> path;
extern stack<car> sk;
const int parkmax=5;
const int pathmax=2;
//#endif // PARKINGLOTINFO_H