When you type m(1) or m(10) in the command window, what is happening?

m(1)
ans = 
    -3 
m(10)
ans = 
    0.6000
m(0)
Array indices must be positive integers or logical
values.

m(0) does not work because it needs to have a positive integer or logical value but what is happening when you do use a correct number?

Answer 1

[Awais Saeed]

Let's say you have an array of 10 elements

arr = [1 2 5 4 7 0 3 6 1 9];

To access first element, you use

arr(1)

ans = 1

to access 5th element, you use

arr(5)

ans = 7

So your m(1) and m(10) means to access first and 10th element of array m. Same goes for a matrix.

[ssmith]

@Awais Saeed and m(0) does not work because there is no 0 element in a matrix?

[John D'Errico]

@ssmith: It is not that the matrix does not contain a zero in it, if that is what you are asking.

MATLAB uses a 1-based index origin. The first element is element number 1. Yes, other languages use a zero origin. But that is just an arbitrary choice. Regardless, m(0) fails, because the zero'th element does not exist.