Dynamic array in java

arrays, java

Solution

An array of dynamic size isn't possible in Java - you have to either know the size before you declare it, or do resizing operations on the array (which can be painful).

Instead, use an `ArrayList<Integer>`, and if you need it as an array, you can convert it back.

List<Integer> sum = new ArrayList<>();
for(int i = 0; i < upperBound; i++) {
    sum.add(i);
}
// necessary to convert back to Integer[]
Integer[] sumArray = sum.toArray(new Integer[0]);

Problem

What i am trying to do is ``` ... int sum[]; ... for(int z.....){ ... sum[z] = some_random_value; ... } ``` But it gives an error at line `sum[z]=ran;` that variable `sum` might not have been initialized. I tried `int sum[] = 0;` instead of `int sum[];` but even that gave an error. (I am basically a C programmer)

Original source