1 
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，我正在尝试从我的 TryAnother 方法中的 getInputArray 方法重复，我尝试使用 do-while 循环但它说 cred1 在 do while 循环中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 表示否）：当然

任何人都可以建议一种方法来执行 do-while 循环吗？先感谢您

我已经编辑了代码，因为当我输入 no 时，由于某种原因它正在执行重复部分，进程不会终止

就像是：

Please enter issuer ID:321321 Please enter account number:654654654 The complete number from your input: 3213 2165 4654 6549
Please enter size of the aray:7 Please enter issuer ID:789789 Credit Card # 0:

7897 8985 6852 9257
Credit Card # 1:

7897 8917 0678 9958
Credit Card # 2:

7897 8900 5781 0934
Credit Card # 3:

7897 8949 2244 6098
Credit Card # 4:

7897 8941 3828 4895
Credit Card # 5:

7897 8965 9233 5006
Credit Card # 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):

as you can see when I enter no it keep repeat the same sentence what i want is for it to repeat from enter the array size sentence how can i do this?

4

2 回答 2

1

I'm not sure what are you expecting as the output of this program. Since you asked about a compile error, I have edited your code and removed two compile errors.

  1. cred1 is not defined in the TryAnother(). Hence you have to pass it as a parameter. Like this TryAnother(CreditCardNumber[] cred1)
  2. In the TryAnother() method, you have put a return true statement in side a if block, but before a do-while loop. This will gives you a unreachable statement compile error, since there is no further execution after executing a return statement in a method. So you have to put the return true statement after the do-while loop.

Here is the corrected code. 

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);         // pass variable cred1 as a parameter
}



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
        {

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



}



// 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;
  }
}

于 2012-11-18T07:53:00.123 回答
0

You should define cred1 as a global static method, outside of the main routine.

Or pass cred1, as a parameter to getInputArray(...), which in turn pass them further, to TryAnother(...).

于 2012-11-18T07:04:46.930 回答