Description
不同交通工具的速度是不同的。针对自行车、摩托车和汽车分别建立类,来模拟这一情况。
定义Vechicle类,是所有交通工具的父类:
属性int speed表示交通工具的一般速度。
静态数据成员int numOfVechicles,表示创建的交通工具的数量。这个值只增不减。
静态成员函数int getNumOfVechicles(),用于获取交通工具的数量。
析构函数。输出“A vechicle is deleted.”
纯虚函数void show().
定义Bike、MotoBike和Car三个类,它们都是Vechicle的子类,且具有:
构造函数。
重写show()函数,输出“A *'s speed is ? km/h.”,其中“*”是bike、motobike或car,根据所在类不同而不同。“?”是speed属性的值。
析构函数。输出“A * is deleted.”,“*”的含义同上。
定义Person类,表示司机:
数据成员string name,是人的姓名。
void drive(Vechicle&)方法,输出“$ drives”, 并调用Vechicle类的show()方法。其中“$”是name的值。
Input
第1行N>0,表示有N个测试用例。
每个测试用例包括一个不含空白符的字符串、一个字符和一个整数。
Output
见样例及题目描述。
Sample Input
3
Tom B 15
Jack M 50
Mary C 100
Sample Output
In beginning, we have 0 vechicles.
Tom drives. A bike’s speed is 15km/h.
A bike is deleted.
A vechicle is deleted.
Jack drives. A motobike’s speed is 50km/h.
A motobike is deleted.
A vechicle is deleted.
Mary drives. A car’s speed is 100km/h.
A car is deleted.
A vechicle is deleted.
At the end, we have 3 vechicles.
HINT
Append Code
append.cc,
int main()
{
int cases, n;
char c;
string name;
Vechicle* vechicle;
cout<<"In beginning, we have "<<Vechicle::getNumOfVechicles()<<" vechicles."<<endl;
cin>>cases;
for (int i = 0; i < cases; i++)
{
cin>>name>>c>>n;
Person person(name);
switch (c)
{
case 'B':
vechicle = new Bike(n);
break;
case 'M':
vechicle = new MotoBike(n);
break;
case 'C':
vechicle = new Car(n);
break;
}
person.drive(*vechicle);
delete vechicle;
}
cout<<"At the end, we have "<<Vechicle::getNumOfVechicles()<<" vechicles."<<endl;
return 0;
}
AC代码
#include <iostream>
using namespace std;
class Vechicle
{
protected:
int speed;
static int numOfVechicles;
public:
Vechicle(int sp=0):speed(sp){++numOfVechicles;}
virtual void show()=0;
virtual ~Vechicle(){cout<<"A vechicle is deleted."<<endl;}
static int getNumOfVechicles(){return numOfVechicles;}
};
int Vechicle::numOfVechicles=0;
class Person
{
protected:
string name;
public:
Person(string na=""):name(na){}
void drive(Vechicle& p){cout<<name<<" drives. ";p.show();}//刚开始一直没有明白"并调用Vechicle类的show()方法",这里是什么意思;
};
class Bike:public Vechicle
{
public:
Bike(int sp=0):Vechicle(sp){}//总是忘记在子类中给直接基类赋值;而且后面给父类赋值的形式总是出错,写成speed(sp);
~Bike(){cout<<"A bike is deleted."<<endl;}
void show(){cout<<"A bike's speed is "<<speed<<"km/h."<<endl;}
};
class MotoBike:public Vechicle
{
public:
MotoBike(int sp=0):Vechicle(sp){}
~MotoBike(){cout<<"A motobike is deleted."<<endl;}
void show(){cout<<"A motobike's speed is "<<speed<<"km/h."<<endl;}
};
class Car:public Vechicle
{
public:
Car(int sp=0):Vechicle(sp){}
~Car(){cout<<"A car is deleted."<<endl;}
void show(){cout<<"A car's speed is "<<speed<<"km/h."<<endl;}
};
int main()
{
int cases, n;
char c;
string name;
Vechicle* vechicle;
cout<<"In beginning, we have "<<Vechicle::getNumOfVechicles()<<" vechicles."<<endl;
cin>>cases;
for (int i = 0; i < cases; i++)
{
cin>>name>>c>>n;
Person person(name);
switch (c)
{
case 'B':
vechicle = new Bike(n);
break;
case 'M':
vechicle = new MotoBike(n);
break;
case 'C':
vechicle = new Car(n);
break;
}
person.drive(*vechicle);
delete vechicle;
}
cout<<"At the end, we have "<<Vechicle::getNumOfVechicles()<<" vechicles."<<endl;
return 0;
}
1、在类外给静态成员赋初值的写法;
2、总是忘记在子类中给直接基类赋值;而且后面给父类赋值的形式总是出错,写成speed(sp);
3、刚开始一直没有明白”并调用Vechicle类的show()方法”,这里是什么意思;