How can you re-initialize an array that was predefined with the value null in Java?-CodePudding

So I am supposed to complete the below program that determines the size of an array based on the int input of the user.

    public static void main(String[] args) {
       Scanner scan = new Scanner(System.in);
       int userInput = -1;
       int[] userData = null;

But the program starts by declaring the array as : int[] userData = null;

It also starts by declaring the user input variable as -1: int userInput = -1;

The problem of the program is based on re-initializing this array using the int variable scanned from the user as the length of the given array: userInput = scan.nextInt(); So I tried to re-initizile the array using the new input: int[] userData = new int[userInput]; But unsurprisingly Java complains since the array was initialized before (and I'm not supposed to change that).

The question is, is there actually a way to build on the given code or do I have to delete their initial declarations and start over?

CodePudding user response：

It may be better to declare and initialize the variables as soon as you need them with appropriate values without having to reassign them:

Scanner scan = new Scanner(System.in);
int userInput = scan.nextInt(); // no need to set to -1
int[] userData = new int[userInput]; // no need to set to null

CodePudding user response：

You can continue writing your program like so:

int[] userdata = null;
userdata = new int[10];
System.out.println(userdata);
System.out.println(userdata.length);

The output of this code is similar to:

[I@3d3fcdb0
10