如何检查二维数组中是否存在所有请求的值？

Question

我对 C++ 比较陌生，并且在编写管理剧院门票的程序时遇到了困难。我尝试自己测试代码的每个部分以找到问题，但找不到问题。我也尝试寻找答案，但找不到任何似乎可以解决此问题的方法。如果用户选择选项 2，TicketRequest 函数应该验证座位的可用性。如果任何请求的席位不存在或不可用，则应返回适当的消息以由客户端程序显示。

我对这个函数有一些问题：

1. 有时它会显示座位信息（请求的座位数量、每个座位的价格、总费用），并且它总是询问用户是否要购买门票，即使座位不存在也是如此。
2. 当我从座位开始请求第 15 排的 30 个座位（最大值）时
3. 当一些请求的席位存在并且可用但其他席位不可用时，它的行为就像所有席位都可用，但如果并非所有席位都可用，则应显示为不可用。目前，它打印的票的座位号超出了数组中现有的数量。

以下是 TicketRequest 函数的代码行：

string TicketManager::TicketRequest(int seatsRequested, int rowRequested, int seatNumber)
{
    bool displayInfo = false;
    ostringstream os;

    os << fixed << showpoint << setprecision(2);

    if (seatsRequested < 1 || seatsRequested > 30 || rowRequested < 1 || rowRequested > 15
    || seatNumber < 1 || seatNumber > 30)
    {
        os << "\nInvalid entry. The seats requested do not exist.\n";
    }
    for (int count = 0; count < seatsRequested; count++)
    {
        seatNumber++;
        if (SeatStructures[rowRequested - 1][seatNumber - 1] == '#')
        {
            cost = seatsRequested * price[rowRequested - 1];
            displayInfo = true;
        }
        else
        {
            return string ("\nSorry, your requested seat(s) is unavailable.\n\n");
        }
    }
    if (displayInfo == true)
    {
        os << "\nRequested seats:  ";
        os << seatsRequested;
        os << "\nPrice per seat: $";
        os << price[rowRequested - 1];
        os << "\nTotal cost: $";
        os << cost;
    }
    return os.str();
}

我将整个程序粘贴到了 pastebin 中，所以这篇文章不会太长。这是链接：http://pastebin.com/ZyZskG4S

Answer 1

假设如下：

struct SeatStructures[TotalRows][TotalSeatsInARows]; 
with TotalRows = 15 and TotalSeatsInARows = 30

现在如果函数被调用 TicketRequest(int seatsRequested, int rowRequested, int seatNumber) 那么下面是参数的有效值：

• 1 <= rowRequested <= 15

• 1 <= seatsRequested <= 30

• 1 <= seatNumber <= 30

• seats will be allocated from seatNumber onwards (i.e inclusive of seatNumber)

现在，除了检查参数的有效值之外，还可以进行另一项检查：

• 1 <= (seatNumber + seatsRequested - 1) <= 30

现在，可以检查函数TicketRequest返回的值是否包含字符串“ERROR”，因为您不能将返回值修改为bool。

函数如下：

string TicketManager::TicketRequest(int seatsRequested, int rowRequested, int seatNumber)
{
    if((1 < seatsRequested) || (seatsRequested > 30))
    {
        return string("ERROR: Invalid number of seats requested.\n");       
    }

    if((1 < rowRequested) || (rowRequested > 15))
    {
        return string("ERROR: Invalid row number requested.\n");        
    }

    if((1 < seatNumber) || (seatNumber > 30))
    {
        return string("ERROR: Invalid seat number requested.\n");       
    }

    //seat number should be between [1 and 30] (both inclusive)
    //(seatNumber + seatsRequested - 1) should be equal to last valid seat number
    if((1 < (seatNumber + seatsRequested - 1)) || ((seatNumber + seatsRequested - 1) > 30)) &&
    {
        return string("ERROR: Invalid seat number or number of seats requested.\n");        
    }

    //if you come till here then all the parameters are valid, so just check the availability of seats.
    int cost = 0;
    for (int sn = seatNumber; sn <= (seatNumber + seatsRequested - 1); sn++)
    {
        if (SeatStructures[rowRequested - 1][sn - 1] == '#')
        {
            //seat is available
            cost += price[rowRequested - 1];            
        }
        else
        {
            return string("ERROR: Sorry, your requested seat(s) is/are unavailable.\n\n");
        }
    }

    //if you come till here then all the seats are available.   
    ostringstream os;
    os << fixed << showpoint << setprecision(2);
    os << "\nRequested seats:  ";
    os << seatsRequested;
    os << "\nPrice per seat: $";
    os << price[rowRequested - 1];
    os << "\nTotal cost: $";
    os << cost;
    return os.str();
}

现在调用函数并检查返回值：

TicketManager obj;
string szResult = obj.TicketRequest(45, 3, 2);
if(szResult.find("ERROR") != string::npos)
{
    //error
    cout << "szResult << endl;
}
else
{
    //success
}

Answer 2

cout << TicketManager1.TicketRequest(seatsRequested, rowRequested, seatNumber);

如果票可用，此行可以返回true 值，如果可用，则可以

bool isTicketAvailable = false;
TicketManager1.TicketRequest(seatsRequested, rowRequested,seatNumber, isTicketAvailable);

if (isTicketAvailable)
{
    cout << "\n\nDo you wish to purchase these seats? (Y/N)";
            cin >> confirmation;
   //do whatever you need here
}

函数参数应该是这样的

string TicketManager::TicketRequest(int seatsRequested, int rowRequested, int seatNumber, bool& isTicketAvailable)