java - 回答"is"时重复方法

Question

package homework4;
import java.util.Scanner;
public class Prog4 {
static Scanner scanner = new Scanner(System.in);
public static void main(String[] args)
{   CreditCardNumber[] cred1;
    CreditCardNumber cred2 = getInput();
    Display("The complete number from your input:", cred2);
    cred1 = getInputArray();
    DisplayArray(cred1);
    TryAnother(cred1);
}

public static CreditCardNumber getInput() {
    String ID;
    String accNum;
    CreditCardNumber tempCred;      
    System.out.printf("Please enter issuer ID:");
    ID = scanner.next();
    System.out.printf("Please enter account number:");
    accNum = scanner.next();
    tempCred = new CreditCardNumber(ID, accNum);

    return tempCred;
}
public static void Display(String ch, CreditCardNumber cred2)
{

    System.out.println(ch);
    System.out.println(cred2.toString().replaceAll(".{4}", "$0   "));       
}

public static CreditCardNumber[] getInputArray()
{
    CreditCardNumber[] tempArray;
    String tempID;
    int size;       
    System.out.printf("Please enter size of the aray:");
    size = scanner.nextInt();
    if(size < 1)
    {
        size = 1;
    }
    tempArray = new CreditCardNumber[size];
    System.out.printf("Please enter issuer ID:");
    tempID = scanner.next();
    for(int i = 0; i < tempArray.length; i++)
    {
        tempArray[i] = new CreditCardNumber();
        tempArray[i].CreateCred(tempID);
    }

    return tempArray;
}

public static void DisplayArray(CreditCardNumber[] cred1)
{
    for(int i = 0; i< cred1.length; i++)
    {
        Display("Credit Card # " + i+":" + '\n', cred1[i]);
    }
    System.out.println();
}

public static boolean TryAnother(CreditCardNumber[] cred1)   // pass cred1 as a parameter
{
    String s;
    System.out.printf("Get more credit card numbers? (n for no):");
    s = scanner.next();
    if(s.charAt(0) != 'N' || s.charAt(0) != 'n')
    {

        do
        {
            TryAnother(cred1);
            cred1 = getInputArray();
            DisplayArray(cred1);                
        }while(s.charAt(0) != 'N' || s.charAt(0) != 'n');       
    }
    return false;   // put the return statement here
}
}

嗨，我正在尝试从 TryAnother 方法中的 getInputArray 方法重复，我用 do-while 循环尝试此操作，但它说 cred1 在 do while 循环内未定义，但是当我尝试为 cred1 创建本地对象时，它给了我错误代码无法访问如果 do-while 循环工作，输出应该是这样的

Enter a credit card issuer number: 321321
Enter an account number: 654654654
The complete number from your input: 
3213 2165 4654 6549

Enter the number of elements in the array: 7
Enter an issuer ID# (6 digits): 789789

Credit Card # 0: 
7897 8931 4062 1219

Credit Card # 1: 
7897 8920 2125 3522

Credit Card # 2: 
7897 8971 9793 0944

Credit Card # 3: 
7897 8979 3216 3090

Credit Card # 4: 
7897 8995 0461 8493

Credit Card # 5: 
7897 8948 8037 5909

Credit Card # 6: 
7897 8966 0251 9953

Get more credit card numbers? (n for no): ok

Enter the number of elements in the array: 3
Enter an issuer ID# (6 digits): 345345

Credit Card # 0: 
3453 4576 6705 1666

Credit Card # 1: 
3453 4548 1163 5684

Credit Card # 2: 
3453 4563 8807 0419

获取更多信用卡号码？ (n 代表否):当然

任何人都可以建议一种执行 do-while 循环的方法吗？预先感谢您

我现在已经编辑了代码，由于某种原因它正在执行重复部分，当我输入“否”时，进程不会终止

类似于:

请输入发行人 ID:321321请输入账号:654654654您输入的完整数字:3213 2165 4654 6549
请输入阵列大小:7请输入发行人ID:789789信用卡#0:

7897 8985 6852 9257
信用卡#1:

7897 8917 0678 9958
信用卡#2:

7897 8900 5781 0934
信用卡#3:

7897 8949 2244 6098
信用卡#4:

7897 8941 3828 4895
信用卡#5:

7897 8965 9233 5006
信用卡#6:

7897 8981 8442 5880

Get more credit card numbers? (n for no):n
Get more credit card numbers? (n for no):n
Get more credit card numbers? (n for no):no
Get more credit card numbers? (n for no):

正如你所看到的，当我输入 no 时，它会重复相同的句子，我想要的是它从输入数组大小的句子开始重复我该怎么做？

Answer 1

我不确定您期望该程序的输出是什么。既然您询问了编译错误，我已经编辑了您的代码并删除了两个编译错误。

1. cred1 未在 TryAnother() 中定义。因此，您必须将其作为参数传递。像这样 TryAnother(CreditCardNumber[] cred1)
2. 在 TryAnother() 方法中，您已将 return true 语句放入 if block 中，但位于 do-while 循环之前。这会给您带来无法访问的语句编译错误，因为在方法中执行 return 语句后不会进一步执行。因此，您必须将 return true 语句放在 do-while 循环之后。

这是更正后的代码。

import java.util.Scanner;
public class Prog4 {<p></p>

<p>static Scanner scanner = new Scanner(System.in);</p>

<p>public static void main(String[] args)
{   CreditCardNumber[] cred1;
    CreditCardNumber cred2 = getInput();
    Display("The complete number from your input:", cred2);
    cred1 = getInputArray();
    DisplayArray(cred1);
    TryAnother(cred1);         // pass variable cred1 as a parameter
}</p>

<p>public static CreditCardNumber getInput() {
    String ID;
    String accNum;
    CreditCardNumber tempCred;<br/>
    System.out.printf("Please enter issuer ID:");
    ID = scanner.next();
    System.out.printf("Please enter account number:");
    accNum = scanner.next();
    tempCred = new CreditCardNumber(ID, accNum);
    return tempCred;
}</p>

<p>public static void Display(String ch, CreditCardNumber cred2)
{
    System.out.println(ch);
    System.out.println(cred2.toString().replaceAll(".{4}", "$0   "));<br/>
}</p>

<p>public static CreditCardNumber[] getInputArray()
{
    CreditCardNumber[] tempArray;
    String tempID;
    int size;<br/>
    System.out.printf("Please enter size of the aray:");
    size = scanner.nextInt();
    if(size < 1)
    {
        size = 1;
    }
    tempArray = new CreditCardNumber[size];
    System.out.printf("Please enter issuer ID:");
    tempID = scanner.next();
    for(int i = 0; i < tempArray.length; i++)
    {
        tempArray[i] = new CreditCardNumber();
        tempArray[i].CreateCred(tempID);
    }
    return tempArray;
}</p>

<p>public static void DisplayArray(CreditCardNumber[] cred1)
{
    for(int i = 0; i< cred1.length; i++)
    {
        Display("Credit Card # " + i+":" + '\n', cred1[i]);
    }
    System.out.println();
}</p>

<p>public static boolean TryAnother(CreditCardNumber[] cred1)   // pass cred1 as a parameter
{
    String s;
    System.out.printf("Get more credit card numbers? (n for no):");
    s = scanner.next();
    if(s.charAt(0) != 'N' || s.charAt(0) != 'n')
    {
        do
        {<br/>
            cred1 = getInputArray();
        }while(s.charAt(0) != 'N' || s.charAt(0) != 'n');
    }
    return false;   // put the return statement here
}</p>

<p>}</p>

<p>// A dummy class
class CreditCardNumber{
  String ID;
  String accNum;
  public CreditCardNumber(){
  }
  public CreditCardNumber(String ID,String accNum){
    this.ID = ID;
    this.accNum = accNum;
  }
  public void CreateCred(String tempID){
    ID = tempID;
  }
}
</p>