只搜索和更改二维数组的一个数目。

Question

首先让我说，这是我在课堂上做的一个“实验室”，我已经为两个程序中的第二个做了大约5个小时的工作，其中两个可能被困在了其中一个部分。让我先告诉你这个程序的要求，这样也许所有这些都会更有意义。

剧院座位表被实现为票价的二维数组，如下所示：

 10 10 10 10 10 10 10 10 10 10 
 10 10 10 10 10 10 10 10 10 10 
 10 10 10 10 10 10 10 10 10 10 
 10 10 20 20 20 20 20 20 10 10 
 10 10 20 20 20 20 20 20 10 10 
 10 10 20 20 20 20 20 20 10 10
 20 20 30 30 40 40 30 30 20 20 
 20 30 30 40 50 50 40 30 30 20
 30 40 50 50 50 50 50 50 40 30

编写一个程序，提示用户选择一个座位或价格。马克通过把价格改为0出售了座位。当用户指定一个座位时，确保它是可用的。当用户指定价格时，请找出该价格的任何位置。

这就是这本书的描述，这也是我的教授给我的建议。

所需的程序组件:此解决方案中的初始座位图是生成的，如示例所示。该解决方案还假定用户将输入一行和座位，从1开始，其中第1行是最下面的前排。您的程序应该至少有3种静态方法，一是打印数组，二是sellSeatByPrice，三是sellSeatByNumber。请声明并初始化您的阵列提供的座位价格值，在主。

我花了大约两个小时才弄明白如何将二维数组中的一个改变为0。假设我输入了一个30的位置，为了让它工作，我已经修改了大约5次代码，我要么每30次更改一个0，或者几个，或者一个也没有。我需要帮助的主要部分是名为sellSeatByPrice()的方法。目前我没有任何数字可以改变。以下是我当前的完整代码：

import java.util.*;
public class Theater
{
   static Scanner in = new Scanner(System.in);
   static int[][] seatingChart;

   public static void main(String[] args)
   {
       seatingChart = new int[][] { 
          { 10, 10, 10, 10, 10, 10, 10, 10, 10, 10 },
          { 10, 10, 10, 10, 10, 10, 10, 10, 10, 10 }, 
          { 10, 10, 10, 10, 10, 10, 10, 10, 10, 10 }, 
          { 10, 10, 20, 20, 20, 20, 20, 20, 10, 10 }, 
          { 10, 10, 20, 20, 20, 20, 20, 20, 10, 10 }, 
          { 10, 10, 20, 20, 20, 20, 20, 20, 10, 10 },
          { 20, 20, 30, 30, 40, 40, 30, 30, 20, 20 },
          { 20, 30, 30, 40, 50, 50, 40, 30, 30, 20 },
          { 30, 40, 50, 50, 50, 50, 50, 50, 40, 30 },
       }; 
       System.out.println("Welcome to the Box Office Program.");                //Introduction Statements
       System.out.println("Please note that seats are arranged such that");
       System.out.println("row 1, column 1, is the bottom front row.");
       System.out.println("Also, a zero denotes the seat is already sold.");
       printSeats(seatingChart);
       char response = 'Y';
       while ((response == 'Y') || (response == 'y'))
       {
       System.out.print("Pick by Seat <s>, Price <p>, or Quit <q>: ");
       char choice = in.next().charAt(0);
           switch (choice)
            {
               case'S':case's':
               { sellSeatByNumber(seatingChart);
                   break; }
               case'P':case'p':
               { sellSeatByPrice(seatingChart);
                   break; }
               case'Q':case'q':
               { System.out.print("Thank you, come again!");
                   System.exit(0); }
               default:
               { System.out.println("Error: Invalid choice."); }
            }
           System.out.print("Would you like to reserve another seat (Y/N)?: ");
        response = in.next().charAt(0);
       }
       System.out.print("Thank you, come again!");
       }

   public static void printSeats(int seatingChart[][])
   {
       for(int i=0; i<seatingChart.length; i++)
       {
           for(int j=0; j<seatingChart[i].length; j++)
           {
               if (j>0)
                   System.out.print("\t");
                   System.out.print(seatingChart[i][j]);
           }
           System.out.println();
       }
   }




   public static void sellSeatByPrice(int seatingChart[][])
   {
       System.out.print("Please enter a price for the seat you would like: ");
       int price = in.nextInt();
       boolean found = false;
       for (int i=0;i<9;i++)
         for (int j=0;j<10;j++)
            if ((found == true)&&(seatingChart[i][j]==price))
            { seatingChart[i][j]=0; break; }

        printSeats(seatingChart);


   }

   public static void sellSeatByNumber(int seatingChart[][])
   {
       System.out.println("Enter a row, then enter a seat number.");
       System.out.print("What row would you like to sit on?:");
       int row = in.nextInt();
       row = Math.abs(row-9);
       System.out.print("What seat of that row would you like to sit in?:");
       int col = in.nextInt();
       col -= 1;
       if (seatingChart[row][col]!=0)
       {
           seatingChart[row][col] = 0;
           printSeats(seatingChart);
           System.out.println("Your seat has been reserved and reflected with a 0 on the chart now.");
       }
       else { System.out.println("Sorry, that seat is already taken."); }
   }
}

(如果这件事看上去很草率，现在是凌晨3点，我不能再想了，我真的很抱歉)

Answer 1

您的方法必须如下所示：

public static void sellSeatByPrice(int seatingChart[][])
{
   System.out.print("Please enter a price for the seat you would like: ");
   int price = in.nextInt();
   // boolean found = false;
   out: for (int i=0;i<9;i++)
     for (int j=0;j<10;j++)
        if (seatingChart[i][j]==price)
        { seatingChart[i][j]=0; break out; } // Notice this change

    printSeats(seatingChart);


}

Answer 2

首先，检查found == true (顺便说一句，它可以缩短为if (found) )。found被初始化为false，再也不会被碰触，所以每次检查都失败。

这里甚至不需要布尔变量。对座位进行迭代；如果一个座位有您要寻找的价格，请将座位的价格设置为0，打印数组并返回(break只退出内部for循环)。