arrays problem

[hugo84]

I'd like to know if by initializing an array it would give you 0000000? when no values are stored
For example:

final static int [] array = new int[11];
By initializing if i display them out it would look like this in my program.
[0] [1] [2] [3] [4] [5] [6] [7] [8] [9] [10]
0 0 0 0 0 0 0 0 0 0 0

Question is So if after initializing they become 0, what if a user inserts a value 0 into the array[1] then how do you differentiate it between a stored 0 and an initialized 0. Im quite confused.


---------------------------------------------------------------------------------------------
This is how i did my Insert Method:
Im actually searching for the key 0(since it is 0 when initialized) then insert a number into it. I dont know if doing this is actually correct?

public static void insert(int[] array, int n) {
         int nElems = 11; // number of items
         int j; // loop counter
         long searchKey; // key of item to search for
         Scanner sc = new Scanner(System.in);
         System.out.print("Enter new number: ");
         n = sc.nextInt();
         
         searchKey = 0; // find item with key 0
         for(j=0; j<nElems; j++) // for each element,
            if(array[j] == searchKey) // found item?
               break; // yes, exit before end
         if(j>array.length-1) // at the end?
            System.out.println("Array Full"); // yes
         else if(j !=nElems) 
            System.out.println("Found" + searchKey); // no
         else if (j == nElems)
            System.out.println("Error Number Not Found"+searchKey);
      //--------------------------------------------------------------
         array[j]=n; //store

[holestary]

I'd like to know if by initializing an array it would give you 0000000? when no values are stored
For example:

final static int [] array = new int[11];
By initializing if i display them out it would look like this in my program.
[0] [1] [2] [3] [4] [5] [6] [7] [8] [9] [10]
0 0 0 0 0 0 0 0 0 0 0

Question is So if after initializing they become 0, what if a user inserts a value 0 into the array[1] then how do you differentiate it between a stored 0 and an initialized 0. Im quite confused.


---------------------------------------------------------------------------------------------
This is how i did my Insert Method:
Im actually searching for the key 0(since it is 0 when initialized) then insert a number into it. I dont know if doing this is actually correct?

public static void insert(int[] array, int n) {
         int nElems = 11; // number of items
         int j; // loop counter
         long searchKey; // key of item to search for
         Scanner sc = new Scanner(System.in);
         System.out.print("Enter new number: ");
         n = sc.nextInt();
         
         searchKey = 0; // find item with key 0
         for(j=0; j<nElems; j++) // for each element,
            if(array[j] == searchKey) // found item?
               break; // yes, exit before end
         if(j>array.length-1) // at the end?
            System.out.println("Array Full"); // yes
         else if(j !=nElems) 
            System.out.println("Found" + searchKey); // no
         else if (j == nElems)
            System.out.println("Error Number Not Found"+searchKey);
      //--------------------------------------------------------------
         array[j]=n; //store

i don't think u can use n like this..n is parameter and must get when u call method..but u try get it after u call method..did it work..

[holestary]

ohh..maybe u send value..but i did not think like that.. but it seems it is not required like that..post your full code..

[hugo84]

Yes it works fine

[jcaccia]

When using int 0 is always 0, whether it is the initial value or was input by the user or read from a file, etc. Using just the int variable, there is no way of identifying where that value came from.

If it is important to determine if a variable's certain value was entered by the user (or any other means) as opposed to been the initial value, you have a few alternatives:

• use an initialisation value that is impossible to be entered by the user
• use a boolean to indicate the variable initial value has been changed
• use an enum to stablish the variable's state (this could be extended to several other states, rather than just initialised and entered by the user)
• use Integer instead of int (initially null, if it has an integer value it must have been entered by the user)

Regarding holestary's post, assigning a new value to a parameter passed to the method will work, but the question is why passing the value n if then you are not using it and you assign a new value? Why not using a local variable for that?

Another question: why is searchKey declared as long when you use it to search for an int value?

An yet another one: why not using a set instead of an array?

[hugo84]

OK. so what im seeing now when i initialize an array i would see 000000000000 is correct.
About that long for searchKey sorry my bad.
About not using set and all those, sorry its an assignment i had to go by the guidelines.

--------------------------------------------------------------------------------------
Another problem:
When i do a remove my method would remove all numbers containing searchKey. How do i delete only the first impression of that number

EG:
After insertion
1,2,3,4,5,6,6,6,8

I want to delete 6, from my codes it would look for all that contains 6 and delete them all
After deletion
1,2,3,4,5,8

What is want is:
After deletion
1,2,3,4,5,6,6,8

[hugo84]

ohh..maybe u send value..but i did not think like that.. but it seems it is not required like that..post your full code..

Yes n is actually in my main method switch case when i pass in the number to the method. Sorry for the messiness i have arleady clean it up. Thanks for the reminder

[dlorde]

i don't think u can use n like this..n is parameter and must get when u call method..but u try get it after u call method..did it work..

Of course you can use it - it's not particularly Good Practice, but there's nothing to stop you, unless the parameter is declared 'final'.

Why not just try it out before posting?

They know enough who know how to learn...
J. Adams

[dlorde]

How do i delete only the first impression of that number

Exit the loop immediately after resetting the number (i.e. in the 'if' block). This points to the value of always using curly braces {} with control statements like 'if'.

Experience is a poor teacher: it gives its tests before it teaches its lessons...
Anon.

[hugo84]

Exit the loop immediately after resetting the number (i.e. in the 'if' block). This points to the value of always using curly braces {} with control statements like 'if'.

Experience is a poor teacher: it gives its tests before it teaches its lessons...
Anon.

Thanks for your pointer. Works now.