Need help understanding - Nesting For Loops

JavaScript
2

The arr array refers to this array:

[
  [1, 2],
  [3, 4],
  [5, 6, 7]
]

When i equals 1, arr[i] refers to the inner array [3, 4]. You can trace it in the diagram. arr points to this array with three blocks. From there the block with the index of 1 (this is i) points to the array that contains the numbers 3 and 4.

When j also equals 1, arr[i][j] refers to the number 4. In the diagram, the block with the index 1 in array [3, 4] contains the number 4.

So arr[i][j] when i and j are both 1 is just the number 4. You multiply this 4 to the number in product (the number 6), so now you have 24.

Related thread:

2 Likes