You probably accidentally assigned a value to a variable named count so that count() in your code is an indexing request instead of a function call.
(Or you might have done so in the past and you had not cleared your variables since then.)
Note:
The part of the instructions about accepting an input character array could be interpreted as expecting you to write a function that takes a parameter that is type char and which is not necessarily a character vector -- for example that it might be valid for the user to pass in
M = ['hi there';
'aminata ']
and that the counts are to be processed for that. If so, then be careful in your code:
MS = string(M)
count(MS, "t")
Notice the result of string() of a character array is one string entry per row of the character array, and that if you count() on a string array that the result is per string entry, not total.
