You are creating an array of zero length (no slots to put anything in)
int array[]={/*nothing in here = array with no slots*/};
and then trying to assign values to array slots (which you don't have, because there are none)
array[i] = number; //array[i] = element i in the array of length 0
You need to define a larger array to fit your needs
int array[] = new int[4]; //Create an array with 4 elements [0],[1],[2] and [3] each containing an int value
You are creating an array of zero length (no slots to put anything in)
int array[]={/*nothing in here = array with no slots*/};
and then trying to assign values to array slots (which you don't have, because there are none)
array[i] = number; //array[i] = element i in the array of length 0
You need to define a larger array to fit your needs
int array[] = new int[4]; //Create an array with 4 elements [0],[1],[2] and [3] each containing an int value
Your code compiles just fine. However, your array initialization line is wrong:
int array[]={};
What this does is declare an array with a size equal to the number of elements in the brackets. Since there is nothing in the brackets, you're saying the size of the array is 0 - this renders the array completely useless, since now it can't store anything.
Instead, you can either initialize the array right in your original line:
int array[] = { 5, 5, 5, 5 };
Or you can declare the size and then populate it:
int array[] = new int[4];
// ...while loop
If you don't know the size of the array ahead of time (for example, if you're reading a file and storing the contents), you should use an ArrayList instead, because that's an array that grows in size dynamically as more elements are added to it (in layman's terms).
You cannot make an empty array and then let it grow dynamically whenever the user enters a number in the command line. You should read the numbers and put them in an ArrayList instead. An ArrayList does not require a initial size and does grow dynamically. Something like this:
public void main(String[] args) {
ArrayList<Integer> numbers = new ArrayList<Integer>();
BufferedReader console =
new BufferedReader(new InputStreamReader(System.in));
while(true) {
String word = console.readLine();
if (word.equalsIgnoreCase("end") {
break;
} else {
numbers.add(Integer.parseInt(word);
}
}
Ofcourse you won't use while(true)and you won't put this in main, but it's just for the sake of the example
How about:
Scanner scan = new Scanner(System.in);
System.out.print("Enter the array size: ");
int size = scan.nextInt();
int[] yourArray = new int[size];
//can even initialize it
Arrays.fill(yourArray, -1);
Empty an array in Java / processing - Stack Overflow
Empty Array
How to create an empty array with a lenght determined by another method ?
[Java] Why can't we create an array of type T?
There's
Arrays.fill(myArray, null);
Not that it does anything different than you'd do on your own (it just loops through every element and sets it to null). It's not native in that it's pure Java code that performs this, but it is a library function if maybe that's what you meant.
This of course doesn't allow you to resize the array (to zero), if that's what you meant by
"empty". Array sizes are fixed, so if you want the "new" array to have different dimensions you're best to just reassign the reference to a new array as the other answers demonstrate. Better yet, use a List type like an ArrayList which can have variable size.
You can simply assign null to the reference. (This will work for any type of array, not just ints)
int[] arr = new int[]{1, 2, 3, 4};
arr = null;
This will 'clear out' the array. You can also assign a new array to that reference if you like:
int[] arr = new int[]{1, 2, 3, 4};
arr = new int[]{6, 7, 8, 9};
If you are worried about memory leaks, don't be. The garbage collector will clean up any references left by the array.
Another example:
float[] arr = ;// some array that you want to clear
arr = new float[arr.length];
This will create a new float[] initialized to the default value for float.