Can someone please explain me arrays

Question

In this code , why do we write arr[i] in line 7 whereas it is not an array index
https://code.sololearn.com/c3gkQhFWkL2w/?ref=app

Answer 1

You have a for loop:
for(int i = 0; i < arr.length, i++)
--> i changes its value from 0 to 2
--> arr.length = size of your array (3 values inside: length = 3)
--> array index start at 0, last index = length-1

i = 0: arr[0] = 54
i = 1: arr[1] = 6
i= 2: arr[2] = 8
end of loop is reached (next value would be 3 but your value have to be smaller than 3)
sum+=arr[i]
sum = sum + arr[0] //54
sum = sum + arr[1] //60
sum = sum + arr[2] //68

An array is like a Drawer. Each subject has an index. With a for loop you can read all values in the subjects.

You can create diffrent arrays:

String[] arr = new String[10]
--> an empty String array (length = 10)
char[] arr = {'a', 'b', 'c')
--> a filled char array (length = 3)

Answer 2

Thank you Denise Roßberg

Answer 3

Your welcome :)