java - 将参数从方法传递到 main

Question

我似乎无法弄清楚我的方法“public static int[][] sellSeatByPrice 的参数应该是什么”。我需要提示用户输入(座位的)价格，然后确定该价格是否被采用(如果它 = 0)，如果没有，则为其分配值 0。

下面是我的代码，请帮忙!

import java.util.Scanner;
/**
 * Write a description of class A10_TheaterSeating here.
 *
 * @author (your name)
 * @version (a version number or a date)
 */
public class A10_TheaterSeating
{
public static void main(String args[])
{
    System.out.println("***Welcome to the Ticket Choice App!***");
    System.out.println();

    int[][] theaterSeats = //set values in seating chart array
    {
        {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}
    };
    int[][] seats = theaterSeats;

    printArray(seats); //print the seating chart
    System.out.println();

    //Defining variables
    String str = "";
    String input = "";

    while (!input.equalsIgnoreCase("Q"))
    {
        System.out.print("Select 'S' to pick a seat, 'P' choose a price or 'Q' to quit:     ");
        Scanner in = new Scanner(System.in);
        input = in.next();

        if (input.equalsIgnoreCase("S"))
        {
            System.out.print("Enter row and seat number desired: ");
            int row = in.nextInt();
            int seat = in.nextInt();
            System.out.println();
            sellSeatByNumber(seats, row, seat);

            printArray(seats);
            System.out.println();
        }
        else if (input.equalsIgnoreCase("P"))
        {
           System.out.print("Enter price of seat desired: ");
           int price = in.nextInt();
           System.out.println();
           sellSeatByPrice(seats, row, seat, price);

           printArray(seats);
           System.out.println();
        }
    }
    System.out.println();
    System.out.println("Thank you for choosing the ticket choice app.");
    System.out.println();
}

public static void printArray(int[][] currSeat)
{
    final int ROWS = 9;
    final int COLUMNS = 10;

    for(int i = 0; i < ROWS; i++)
    {
        for (int j = 0; j < COLUMNS; j++)
        {
            System.out.print(currSeat[i][j] + "\t");
        }
        System.out.println();
    }
}

public static int[][] sellSeatByNumber(int[][] seats, int row, int seat)
{
    if (row <= 0 || row > 9)
    {
        if (seat <= 0 || seat > 10)
        {
            System.out.print("Please enter a valid row and seat: ");
        }
    }
    if (seats[row][seat] == 0)
    {
        System.out.print("That seat is taken. Please select another seat: ");
    }
    else
    {
        seats[seats.length - row][seat - 1] = 0;
    }
    return seats;
}

public static int[][] sellSeatByPrice(int[][] seats, int row, int seat, int price)
{
    if (seats[row][seat] = price)
    {
        seats[seats.length - row][seat - 1] = 0;
    }
    return seats;
}
}

Answer 1

您的参数看起来不错 - 内部逻辑和语法不正确。

由于您使用的是 static 方法，并传递座位矩阵，这没问题 - 但您必须检查传入的值是否在矩阵的范围内 - 或者您将获得异常(exception)情况。

例如，您不检查 sellSeatByPrice() 中的边界。你真的应该这样做，否则伪造的行/座位组合可能会破坏你的计划。

同样是给出的比较不正确:

if (seats[row][seat] = price)

应该是

if (seats[row][seat] == price)

= 是赋值，== 是原始比较。

此外，在 sellSeatByNumber() 中，您仍然会遇到问题，因为越界行/座位组合仍然会爆炸。您确实检查了边界 - 荣誉 - 但如果它们超出了这些边界，您就不会返回任何东西。实际上，如果它们越界，则应引发 IllegalArgumentException，或者您可以返回未修改的矩阵(这可能更直接)。