Answer 1

if int i is local variable declared in method there is not default value
public static void main(String[] args) {
int i;
System.out.println(i); // error: variable i might not have been initialized
}

Answer 2

Hi Saeed Haghighi
Please use proper tags with your question. It will help others finding this question to others. Happy Coding ☺

Answer 3

It's best to define your variables at declaration time.

Answer 4

If you don't initialize static variables they get default. Int 0, double 0.0 and so on.

https://code.sololearn.com/c5NfHaf0d8Xh/?ref=app

Edit: change the print statement to see all default values.

Answer 5

O i think