Java int array malformed declaration

Question

i have a question regarding java int array initialization. i want to set the widths base on conditions, but when i try to compile it says malformed declaration. Anything wrong with my array initialization?

int []widths;
if(condition 1)
{
   widths = {1,4,5,3};
} 

if(condition 2)
{
   widths = {1,9,5,3,2};
}  

method1.setWidth(widths );  //method that take int array as argument.

Eran · Accepted Answer · 2015-03-10 06:42:50Z

3

widths = {1,4,5,3} is only valid when it's part of the declaration of the array variable.

change your code to :

int[] widths;
if(condition 1) {
   widths = new int[] {1,4,5,3};
} 

if(condition 2) {
   widths = new int[] {1,9,5,3,2};
}  

method1.setWidth(widths);

You should also consider giving the widths array a default value, in case neither of your two conditions is true, since your code wouldn't pass compilation otherwise.

It can be something like this :

int[] widths = null;
if(condition 1) {
   widths = new int[] {1,4,5,3};
} 

if(condition 2) {
   widths = new int[] {1,9,5,3,2};
}  

if (widths != null) {
    method1.setWidth(widths);
}

edited Mar 10, 2015 at 6:42

answered Mar 10, 2015 at 6:36

Eran

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2 Comments

hades Over a year ago

the method1.setWidth(widths); shows Error(509,29): variable widths might not have been initialized

glglgl Over a year ago

In Java8 you can do Optional<int[]> widths = Optional.empty();, later widths = Optional.of(new int[] {1,9,5,3,2}); and at the end you just do widths.ifPresent(method1::setWidth).

riccardo.cardin · Accepted Answer · 2015-03-10 06:59:33Z

0

The answer given by @Eran was the correct one. But, if you still need an array and you not know in advance how many element the array will contain, try to get a look at List: <T> T[] toArray(T[] a) method.

This way, your example should become:

List<Integer> list = new ArrayList<Integer>();
if (condition 1) {
   // Fullfil the list in some way
} else if (condition 2) {
   // Fullfil the list in some other way
} 
// The array given in input to toArray is needed cause type erasure of 
// generics at compile time.
method1.setWidth(list.toArray(new Integer[list.size()]));

Clearly, you can't use array of primitive types this way.

answered Mar 10, 2015 at 6:59

riccardo.cardin

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