java方法删除数组

Question

I am currently stuck on a java question where i have no idea how to proceed.. really appreciate any help!

The question is:

Write a java method, the method receives an integer number indicating the number of accounts, the array that contains the login names and the corresponding passwords and index of the account to be removed. It deletes the name and password of the account if removeindex is within the acceptable range. The method returns the updated number of accounts.

removeIndex : the index of the account to be removed

*Assuming arraysize is already created at other methods.

 public static int removeAccount(int count, String[] nameArr, String[] paswordArr, int removeIndex){

    for(int i=0; i<count;i++){
        String target = nameArr[removeIndex];
        if(target != null){
            // what should i do here?

        }else{
           System.out.println("id does not exist");

       }

    }
    return count;
}

Answer 1

First, you can't "remove" anything from an array; once it is created, its size is fixed. Therefore it is assumed here that what you want is to set the matching value to null if it isn't already.

It is also assumed that the count is within bounds...

Code:

if (removeIndex >= nameArr.length)
    return count;

if (nameArr[removeIndex] == null)
    return count;

nameArr[removeIndex] = null;
passwordArr[removeIndex] = null;

return count - 1;

---

Now, the question is imprecise. Say you have an array with elements:

[ x, y, z ]

and the removal index is 1. What do you want the contents of the array to be after the operation? Is that [ x, null, z ] or [ x, z, null] ? The code above assumes the former.

Answer 2

Tested Code

Try this code. I've used an ArrayList to store accounts information.

public class Test {
public static ArrayList accounts=new ArrayList();
public static Scanner scan;
public static void main(String args[]){
    System.out.println("Enter number of accounts to add:");
    scan=new Scanner(System.in);
    int number=scan.nextInt();

    addAccount(number);

    System.out.println("Enter index(account no.) to remove account:\n(e.g. 1,2,3 etc)");
    int removeIndex=scan.nextInt();

    number=removeAccount(number,removeIndex);
    System.out.println("Number of accounts: "+number);
}
public static void addAccount(int n){
    scan=new Scanner(System.in);
    for(int i=0;i<n;i++){
        System.out.println("Enter Username for account "+(i+1)+":");
        accounts.add(scan.nextLine());
        System.out.println("Enter Password for account "+(i+1)+":");
        accounts.add(scan.nextLine());
    }
    System.out.println("Accounts added: "+accounts);
}
public static int removeAccount(int n, int index){
    String target = (String) accounts.get((index*2)-2);
    if(accounts.contains(target)){
        accounts.remove((index*2)-2);
        accounts.remove((index*2)-2);
    }
    System.out.println("After Deletion: "+accounts);
    return n-1;
}

}

---

How it works:

1. It takes no. of accounts to be added.
2. Adds username and password specified no. of accounts into ArrayList .
3. Asks for account no. to be deleted.
4. Deletes the record of given account no.