带有数组的JAVA if语句不起作用

Question

我正在尝试构建一个书票系统，但我的代码无法正常工作，没有错误只是我预期的结果无法得到 这是我的代码，谁能告诉我我的代码哪里出了问题？

 public class Train  {
 public static void book(){

 int dest,sno;
 char[] seat1=new char [9];

 Integer Tid=1;

 Scanner sc= new Scanner(System.in);
 Scanner sc2=new Scanner(System.in);
 for(int i=0; i<9; i++)
{
    seat1[i]='A';
}
 System.out.println("Where do you want to go?");
  System.out.println("1. Main Entrerance to Night Safari");
  System.out.println("2. Main Enterance to River Safari");
  System.out.println("3. River Safari to Main Enterance");
  dest=sc.nextInt();
if (dest==1 && Tid !=null)
  {
System.out.println("_1"+seat1[0]+"_|_2"+seat1[1]+"_|_3"+seat1[2]+"_");
  System.out.println("_4"+seat1[3]+"_|_5"+seat1[4]+"_|_6"+seat1[5]+"_");     
  System.out.println("_7"+seat1[6]+"_|_8"+seat1[7]+"_|_9"+seat1[8]+"_");
  System.out.println("Enter seat number to select seat:");
  sno=sc.nextInt();

  if(sno>=1 && sno<=9)
{
    if(seat1[sno-1]!='B')
    {

        seat1[sno-1]='B';

        book();//here is working, it will go back again but when I re enter book(); and select dest1 agn it doesn't changed selected sno to B
    }

    else
    {
        System.out.println("Seat Already Booked, Choose Another ");

       book();
    }

}
}

else
{
    System.out.println("Invalid Seat Number, Select Again ");

    book();
}
}
}

输出如我预期的那样显示

1A|_2A_|3A _4A_|5A|_6A_ 7A|_8A_|9A 但是当我选择一个座位并再次返回时，它并没有像我预期的那样将所选座位从 A 更改为 B

Answer 1

轻松修复。您将递归方法与方法book() 一起使用。您希望编辑数组seat1，但每次调用book() 方法时，都会使用初始值重新创建数组。

解决方法是在调用第一个 book() 方法之前创建另一个方法，如下所示：

public static void initArray() {
     for(int i=0; i<9; i++)
     {
        seat1[i]='A';
     }
}

然后在book方法中删除数组的创建。

注意：您必须通过将private static char[] seat1=new char [9]; 放在public class Train { 下，使数组char[] seat1=new char [9]; 成为类的属性

更新： 整个课程更新：

package javaapplication19;

import java.util.Scanner;

public class Train {

    static char[] seat1 = new char[9];

    public static void book() {

        int dest, sno;

        Integer Tid = 1;

        Scanner sc = new Scanner(System.in);
        Scanner sc2 = new Scanner(System.in);

        System.out.println("Where do you want to go?");
        System.out.println("1. Main Entrerance to Night Safari");
        System.out.println("2. Main Enterance to River Safari");
        System.out.println("3. River Safari to Main Enterance");
        dest = sc.nextInt();
        if (dest == 1 && Tid != null) {
            System.out.println("_1" + seat1[0] + "_|_2" + seat1[1] + "_|_3" + seat1[2] + "_");
            System.out.println("_4" + seat1[3] + "_|_5" + seat1[4] + "_|_6" + seat1[5] + "_");
            System.out.println("_7" + seat1[6] + "_|_8" + seat1[7] + "_|_9" + seat1[8] + "_");
            System.out.println("Enter seat number to select seat:");
            sno = sc.nextInt();

            if (sno >= 1 && sno <= 9) {
                if (seat1[sno - 1] != 'B') {

                    seat1[sno - 1] = 'B';

                    book();//here is working, it will go back again but when I re enter book(); and select dest1 agn it doesn't changed selected sno to B
                } else {
                    System.out.println("Seat Already Booked, Choose Another ");

                    book();
                }

            }
        } else {
            System.out.println("Invalid Seat Number, Select Again ");

            book();
        }
    }

    public static void init() {
        for (int i = 0; i < 9; i++) {
            seat1[i] = 'A';
        }
    }
}

它给出以下输出：

运行：

你想去哪里？

1. 夜间野生动物园主入口

2. 河川生态园主入口

3. River Safari 到主入口

1

1A|_2A_|3A

4A|_5A_|6A

7A|_8A_|9A

输入座位号选择座位：

2

你想去哪里？

1. 夜间野生动物园主入口

2. 河川生态园主入口

3. River Safari 到主入口

1

1A|_2B_|3A

4A|_5A_|6A

7A|_8A_|9A

输入座位号选择座位：

这不是你想要的吗？