creating array at runtime

[javaplus]

Hi,

I want to create an array at run time. I am not sure about its size when coding. I take an input from user through console and then want to create the array of that size.

Code:

int[] array = new int [5];

In the example above, I mentioned the size which is fine. I just want to know if size can be given later?

Is this possible? How?

Thanks.

[hardwired]

if size can be given later
No. You have to instantiate an array with a size. You can change the size later by making a new array of the same type at a different size and copying the elements of the old array into it - actually assigning the new elements the value of the old elements. The System.arraycopy method is useful for this.

[hiranya]

You could do something like this.

Code:

int[] array = new int[size];

Here size is an integer variable with some value. If the value of 'size' is determined at the runtime then your array size will be determined at runtime.

Regards,
Hiranya

[javaplus]

Thanks. Its helps.

[hardwired]

I just want to know if size can be given later?
You can re/instantiate the array at any time.

Code:

class Pseudo {
    int[] sizes;                  // declaration
    String[] ids = new String[0]; // declaration and instantiation;

    void someMethod() {
        // Instantiate the sizes array declared as a member variable.
        // Java assigns each element the default value of zero.
        sizes = new int[16];
        // Instantiate the ids array declared and insantiated as a
        // (zero-length array) member variable.
        // Each element of this array is null.
        ids = new String[4];
    }
}