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我有点想完成这个程序

评估要求我们根据下面提供的信息，实施 RockConcert 和 TicketHolder 类。TicketHolder 类代表为特定音乐会的入场费付费的人。这个 TicketHolder 类应该跟踪它的成本和座位的位置。

考虑到提供的驱动程序，我已经构建了大部分代码，但我对如何编写 RockConcert::sellTicket 和 RockConcert::getTicket 方法感到非常困惑

下面是代码，

万分感谢！

TicketHolder.h

#ifndef TicketHolder_h
#define TicketHolder_h
#include <string>
#include <iostream>

using namespace std;

class TicketHolder {

public:
    TicketHolder();
    TicketHolder( std::string seat, double cost );

    std::string getSeat() const;
    double getCost() const;

    friend std::ostream& operator<< (std::ostream& os, const TicketHolder & t);

private:
    std::string my_Seat;
    double my_Cost;
};

#endif

TicketHolder.cpp

#include "TicketHolder.h"


TicketHolder::TicketHolder(){

}
TicketHolder::TicketHolder( std::string seat, double cost ){
    my_Seat = seat;
    my_Cost = cost;
}

std::string TicketHolder::getSeat() const{
    return (my_Seat);
}

double TicketHolder::getCost() const{
    return (my_Cost);

}

std::ostream& operator<< (std::ostream& os, const TicketHolder & t){
    return os;
}

摇滚音乐会.h

#ifndef RockConcert_h
#define RockConcert_h
#include <string>
#include <iostream>
#include <stdexcept>
#include "TicketHolder.h"
#include "SeatAlreadySold.h"
#include "SeatNotFound.h"

class RockConcert {

public:
    public:
    RockConcert( std::string date, std::string location );

    void sellTicket( std::string seat, double cost ) throw (SeatAlreadySold);
    TicketHolder getTicket( std::string seat ) throw (SeatNotFound);
    double getProceeds( );

    friend std::ostream& operator<< ( std::ostream& out, const RockConcert & r );


private:
        TicketHolder myTickets[ 20 ];
        int myNumberOfTicketsSeenSoFar;
        std::string my_When;
        std::string my_Where;

    };

#endif

摇滚音乐会.cpp

    #include "RockConcert.h"
    #include "TicketHolder.h"

    RockConcert::RockConcert( std::string date, std::string location ) {
        my_When = date;
        my_Where = location;
    }

    void RockConcert::sellTicket( std::string seat, double cost ) throw (SeatAlreadySold){

    }

    TicketHolder RockConcert::getTicket( std::string seat ) throw(SeatNotFound) {


    }

    double RockConcert::getProceeds( ){
        return (myNumberOfTicketsSeenSoFar);

    }

    std::ostream& operator<< ( std::ostream& out, const RockConcert & r ){
        return out;
    }

驱动程序.CPP

// driver
// function main
#include "TicketHolder.h"
#include "RockConcert.h"
#include <iostream>
#include <stdexcept>

int main(int argc, const char * argv[])

{
RockConcert megaDeath( "Sept 1", "Staples Center" );
megaDeath.sellTicket( "Row Q Seat 20", 120.00 );
megaDeath.sellTicket( "Row Q Seat 21", 120.00 );
megaDeath.sellTicket( "Row SSS Seat 12", 50.00 );
TicketHolder ticket = megaDeath.getTicket( "Row Q Seat 21" );

// Print out the concert and its tickets
std::cout << megaDeath << std::endl;


try {


    megaDeath.sellTicket( "Row T Seat 30", 65.00 );

} catch( SeatAlreadySold sas ) {

    std::cout << "An error occurred here for the reason:";
    std::cout << sas.what(std::endl:endl;
}

// Print out the library and its book - notice the difference
std::cout << megaDeath << std::endl;
// Let's try to throw some errors...
try {
    // can't sell a ticket that has already been sold
    megaDeath.sellTicket( "Row Q Seat 21", 120.00 );
    std::cout << "An error occurred here..." ;
} catch( SeatAlreadySold sas ) {
    sas.what();
}

try {
    // can't get a ticket that has not been sold
    megaDeath.getTicket( "Row A Seat 1" );
    std::cout << "An error occurred here..." ;
} catch( SeatNotFound snf ) {
    snf.what();
}

}
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1 回答 1

1

我不确定这里的问题到底是什么，但我倾向于创建一个std::map映射票 ID（只要你是一致的，它可以是一个像“Row ## Seat ##”这样的字符串）到一个TicketHolder实例。您的TicketHolder课程（我认为最好命名为 just Ticket）应该包含一个布尔“已售”属性。

在你的getTicket()方法中，一个简单的查找std::map就可以了，而且非常快。

您的sellTicket()方法应首先调用getTicket()，然后检查返回票的“已售”属性（如果已售出则抛出异常）。如果没有，则设置TicketHolder::sold = true. 您还应该将门票成本添加到迄今为止的总收益中。

其他可能有用的一般规则：

  • 尽可能在构造函数中使用初始化列表
  • 避免在 C++ 中使用异常说明符，它们可能不会像你想的那样做
  • 除非你真的知道自己在做什么，否则总是按值抛出异常，并通过 const 引用捕获异常。
  • 避免std::string在函数参数中复制 s 和其他复杂对象
  • 同样，请仔细考虑您的方法返回类型何时应为副本、何时应为引用、何时应为 const 引用以及何时应为（智能）指针。
于 2013-10-28T05:22:27.267 回答