A.3
B.7
C.6
D.4
若已定义了类Vehicle，则下列派生类定义中，错误的是A．class Car：Vehicle{／*类体略*／)；B．class Car：public Car{／*类体略*／)；C．class Car：public Vehicle{／*类体略*／)；D．class Car：virtual public Vehicle{／*类体略*／)；
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若vehicle=['train','bus','car','ship'],则vehicle[1]是什么?A.trainB.busC.carD.ship
若vehicle=['train','car','bus','subway','ship','bicycle','car'],则vehicle.count('car')结果是什么?A.carB.7C.1D.2
若vehicle=[['train','car'],['bus','subway'],['ship','bicycle'],['car']],则len(vehicle)结果是什么?A.1B.7C.6D.4
若vehicle=['train','bus','car','ship'],则vehicle.index('car')的结果是什么?A.1B.2C.3D.4
若vehicle=[['train','car'],['bus','subway'],['ship','bicycle'],['car']],则len(vehicle[1])结果是什么?A.2B.7C.6D.4
阅读以下说明和C++代码，填充代码中的空缺，将解答填入答题纸的对应栏内。【说明】某应急交通控制系统(TraficControISy ,tem)在红灯时控制各类车辆(Vehicle)的通行，其类图如图5-1所示，在紧急状态下应急车辆红灯时也可通行，其余车辆按正常规则通行。下面的C++代码实现以上设计，请完善其中的空缺。include include using namespace std;class Vehicle {／*抽象基类，车辆*／public :virtual void run () = 0;}；class Emergency（ ／*抽象基类，可在红灯时通行的接口，函数均为纯虚函数*／public：(1)=0 ／／isEmergent()函数接口(2)=0 ／／runRedLight()函数接口};class Car: public Vehicle {public :-car(){ }void run () { /*代码略*/ }};Ciass Truck:public vehicie {Public;-Truck(){ }Void run() { /*代码略*/}};Class policecar: (3) {Private:bool isEmergency;public :PoliceCar () : Car () , Emergency () { this=>isEmergency = false;}PoliceCar (bool b) : Car () , Emergency () { this=>isEmergency = b; }～PoliceCar () { }bool isEmergent () { ret irn (4) ； }void runRedLight () { /*代码略*/ }};/*类Ambulance. FireEngine/*实现代码略*/class TraficControISystem {／*交通控制类*/private :Vehicle*v[24]； int numVeh: cles.／*在构造函数中设置初始值为0*／public：void control(){ ／／控制在紧急情况下应急车辆红灯通行，其他情况按常规通行for (int i = 0; iadd (new Car () );, t cs->add (new PoliceCar ()) ;tcs->add (new Ambulance ()) ; tcs- >add (new Ambulance (true)) ;tcs->add (new FireEngine (true)) ; -.cs->add (new FireEngine ()) ;tcs->add (new Truck ()) ;tcs->control () ; tcs->shul Down ( ) ;delete tcs;}
