Lesson 17. Introduction to For Loops: Explain why we need to subtract 1 to board_size.x

[sin3to1faith]

In the second example of this section's lesson, board_size.x - 1 is used as a parameter in the range() function when it should be board_size.x as void range(length: int) creates a list of numbers from 0 to length - 1.

This mistake can be seen again in the first practice lesson 'Using a for loop to move to the end of the board'. The user must recreate the mistake shown in this lesson's example to succeed in the practice lesson.

[NathanLovato]

Thanks for taking the time to give feedback. In this case, the lesson's correct. To move to the end of a grid of 5 cells, if you're on cell 1, you need to move 4 times. range(5) (the size of the array) would produce 5 numbers (0, 1, 2, 3, 4) and make you move 5 steps, so 1 cell past the limit. That's why you need to subtract 1 from the board size.

I'm changing the issue title to add a new sentence about that to the lesson.

[sin3to1faith]

if you're on cell 1

I'm guessing cell 1 refers to the 0 on y in Vector2? My apologies for the oversight. I assumed there was a "cell 0" and forgot that it was just an index.

Is it correct to presume that we can use range(board_size.x) if the robot is not already on the board?