Problem B: 来开个书店吧

墨蓝 2022-06-17 12:56 171阅读 0赞

## Problem B: 来开个书店吧 ##

Time Limit: 1 Sec   Memory Limit: 128 MB  
Submit: 1343   Solved: 776  
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## Description ##

某出版社可出版图书和磁带。其中图书按照每页的价格乘以页数进行定价，磁带根据每10分钟的价格乘以磁带录音的分钟数进行定价。请定义Publicatioin、Book、Tape以及BookStore四个类。其中：

1. Publication类：

1）数据成员double price表示单价（对于书，是每页的价格；对于磁带，是每10分钟录音的价格）。

2）数据成员int length表示出版物的长度，对于书，是页数；对于磁带， 是分钟数。

3）成员函数getTotalPrice()用于返回一个出版物的定价。

4）构造函数Publication(double, int)用于构造一个出版物。

5）成员函数double getPrice() const和int getLength()用于返回出版物的单价及长度。

6）析构函数。

2. Book类是Publication的子类。

1）构造函数Book(double,int)。

2）重写父类的getTotalPrice返回定价，定价为单价乘以长度（即页数）。

3）析构函数。

3. Tape是Publication的子类：

1）构造函数Tape(double,int)。

2）重写父类的getTotalPrice返回定价。注意：price属性是每10分钟录音的单价，而磁带的长度不一定是10的整数倍。计算定价时，不足10分钟部分，按照10分钟计算。

3）析构函数。

4.BookStore是书店，具有数据成员Publications \*\*pubs，是书店拥有的出版物列表；int num表示书店拥有的出版物数量。成员函数int getNumOfBook()和int getNumOfTape()分别计算书店中拥有的Book和Tape的数量。该类已经在appcode code中给出。

## Input ##

输入分多行。

第一行是整数M>0，表示有M个测试用例。

每个测试占一行，分为三部分：第一部分是出版物类型（B表示Book，T表示Tape）、单价和数量（页数或分钟数）。

## Output ##

见样例。

## Sample Input ##

3B 0.10 201T 0.50 100T 0.40 105

## Sample Output ##

Call Publication's constructor!Call Book's constructor!Call Publication's constructor!Call Tape's constructor!Call Publication's constructor!Call Tape's constructor!Call Publication's constructor!Call Book's constructor!Call Publication's constructor!Call Tape's constructor!Call Publication's constructor!Call Tape's constructor!There are 1 books and 2 tapes. Their total price is 29.50.Call Book's de-constructor!Call Publication's de-constructor!Call Tape's de-constructor!Call Publication's de-constructor!Call Tape's de-constructor!Call Publication's de-constructor!Call Book's de-constructor!Call Publication's de-constructor!Call Tape's de-constructor!Call Publication's de-constructor!Call Tape's de-constructor!Call Publication's de-constructor!Call BookStore's de-constructor!

## HINT ##

使用typeid判断对象指针指向的实际对象的类型。

#include <bits/stdc++.h>
    using namespace std;
    
    class Publication
    {
    public:
        double price;
        int length;
        Publication(double price=0,int length=0):price(price),length(length){cout<<"Call Publication's constructor!"<<endl;}
        virtual double getTotalPrice(){}
        double getPrice()const{return price;}
        int getLength(){return length;}
        virtual ~Publication(){cout<<"Call Publication's de-constructor!"<<endl;}
    
    };
    class Book:public Publication
    {
    public:
        Book(double _price,int _length):Publication(_price,_length){cout<<"Call Book's constructor!"<<endl;}
        double getTotalPrice()
        {
            return price*length;
        }
        ~Book(){cout<<"Call Book's de-constructor!"<<endl;}
    };
    class Tape:public Publication
    {
    public:
        Tape(double _price,int _length):Publication(_price,_length){cout<<"Call Tape's constructor!"<<endl;}
        double getTotalPrice()
        {
            double ans=0;
           if(length%10)
                ans += 1+length/10;
           else ans=length/10;
           return ans*1.0*price;
        }
        ~Tape(){cout<<"Call Tape's de-constructor!"<<endl;}
    };
    class BookStore
    {
    private:
        Publication **pubs;
        int num;
    public:
        BookStore(Publication **p, int n)
        {
            pubs = new Publication*[n];
            num = n;
            for (int i = 0; i < n; i++)
            {
                if (typeid(*(p[i])) == typeid(Book))
                {
                    pubs[i] = new Book(p[i]->getPrice(), p[i]->getLength());
                }
                else
                {
                    pubs[i] = new Tape(p[i]->getPrice(), p[i]->getLength());
                }
            }
        }
        int getNumOfBook()
        {
            int c = 0;
            for (int i = 0; i < num; i++)
            {
                if (typeid(*(pubs[i])) == typeid(Book))
                    c++;
            }
            return c;
        }
        int getNumOfTape()
        {
            int c = 0;
            for (int i = 0; i < num; i++)
            {
                if (typeid(*(pubs[i])) == typeid(Tape))
                    c++;
            }
            return c;
        }
        ~BookStore()
        {
            for (int i = 0; i < num; i++)
            {
                delete pubs[i];
            }
            delete[] pubs;
            cout<<"Call BookStore's de-constructor!\n";
        }
    };
    int main()
    {
        int cases, date;
        char type;
        double total,price;
        Publication **pub;
        cin>>cases;
        pub = new Publication*[cases];
        for (int i = 0; i < cases; i++)
        {
            cin>>type>>price>>date;
            switch(type)
            {
            case 'B':
                pub[i] = new Book(price,date);
                break;
            case 'T':
                pub[i] = new Tape(price,date);
                break;
            }
        }
        BookStore bookStore(pub, cases);
        cout<<"There are "<<bookStore.getNumOfBook()<<" books and "<<bookStore.getNumOfTape()<<" tapes.";
        total = 0;
        for (int i = 0; i < cases; i++)
        {
            total += pub[i] -> getTotalPrice();
        }
        cout<<" Their total price is "<<setprecision(2)<<fixed<<total<<"."<<endl;
        for (int i = 0; i < cases; i++)
        {
            delete pub[i];
        }
        delete[] pub;
        return 0;
    }

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