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How the array size is auto increment in java program my requirement is "create a 2 dimensional array sno, in the first dimension name, age in the second dimension so if i pass sds, 25 it should be added to the array [0][sds,25] the array should keep incrementing" my code is like this:

void values() throws IOException{for ( int row = i; row < len; row++ ){
            for ( int column = 1; column <= 1; column++ ){
                arrayValues[row][0] = String.valueOf(row+1);
                System.out.print("Enter "+(row+1)+" Name: ");
                String name = br.readLine();
                System.out.print("Enter "+(row+1)+" age: ");
                int age = Integer.parseInt(br.readLine());
                arrayValues[row][column]= name+","+age;
            }
void incrementSize() throws IOException{String[][] newArray = new String[arrayValues.length][];
    System.out.println(newArray.length);
String[][] t = Arrays.copyOf(arrayValues, newArray.length);

After this how can done my code Please help me

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3  
Sounds like you should be using a different data structure. Have a look at arraylist. –  SBI Jun 11 '13 at 6:52
 
No boss is said to me implement this way only –  Durgaprasad Jun 11 '13 at 7:22
1  
May be he is testing you that weather you are aware of arraylist or not :) –  sᴜʀᴇsʜ ᴀᴛᴛᴀ Jun 11 '13 at 8:15
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4 Answers

up vote 4 down vote

I think the perfect bet of your requirement is ArrayList.

Resizable-array implementation of the List interface.

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1  
What is the reason ?? –  sᴜʀᴇsʜ ᴀᴛᴛᴀ Jun 11 '13 at 7:07
1  
If you want to use arrays for resizable arrays you'll end up recreating what arraylist does "under the hood" anyway (probably less efficiently). I really would check you boss doesnt want arraylists –  Richard Tingle Jun 11 '13 at 8:10
1  
P.s. why are you throwing away all the object orientated nature and going with a 2D array rather than a 1D array of Person objects (each with a name and age field). As you're doing it now you're holding age in a String, that makes me very sad –  Richard Tingle Jun 11 '13 at 8:13
1  
Yeah,It is like using steps ,when you have lift :). –  sᴜʀᴇsʜ ᴀᴛᴛᴀ Jun 11 '13 at 8:14
1  
May be your boss is testing you that weather you are aware of arraylist or not :) –  sᴜʀᴇsʜ ᴀᴛᴛᴀ Jun 11 '13 at 8:17
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up vote 1 down vote

You have to create a new array in order to make the size bigger, there is no dynamic way to increase an existing array.

Here is a way you can create a new array to increase the size. 

int[] a = new int[5];
// fill a
int[] b = Arrays.copyOf(a, 10);
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for single is ok, but how is 2-D and if i can do this way that shows null pointer wxception –  Durgaprasad Jun 11 '13 at 7:07
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up vote 1 down vote

Use List for this requirement. You can use a ArrayList<ArrayList> in place of 2-dim array. ArrayList is Resizable-array implementation of the List interface.

An array is a container object that holds a fixed number of values of a single type.

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up vote 0 down vote

Sounds like you are looking a dynamically growing data structure. you can use implementation of list interface which is in java collection frame work. you can use ArrayList or Vectors.

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