Calculating the maintenance costs over (x) amount of years

Hey forum This is my first time using Mat-lab and the forums. I have been having trouble with both the conceptual aspect, Mat-lab syntax and the debugging the final solution the problem.

The question is asked as follows

A machine requires $2,000 in maintenance every 2 years, $3,500 maintenance every 5 years, and a major overhaul costing $11,300 every 7 years. Use a for-loop to determine the accumulated maintenance costs of the machine over the next x years. Assume that you are starting at Year 0 (i.e. first expense occurs at Year 2). Ex. accumYears(5) = 7500

Here is my attempt at a solution function

function sum = accumYears(x)
for i = 1:1:x
  [q, r] = quorem(i,sym(2));
  if r == 0
  a(i) = 2000;
  end
[q, r] = quorem(i,sym(5));
  if r == 0
  a(i) = a(i) + 5000;
  end
[q, r] = quorem(i,sym(7));
  if r == 0
  a(i) = a(i) + 11300;
  end 
end
sum = sum(a);
end

I receive the error Undefined function or variable "sum".

Error in faccumYears (line 16) sum = sum(a);

Answer 1

[MA]

sum is a built-in matlab function, you should name your function or matric something else like cost

cost = accumYears(x)
cost = sum(a)

Answer 2

[Matthew Abarca]

I've tried the suggested changes and part of the test suite returns fail. On Matlab the code works until the next if statement nested in the for loop. I've recently learned about the mod function but would still like to better understand the quorem function. Why does the second input have to be sym(n) instead of just integer n. This is the error I receive when running the code:

Attempted to access a(5); index out of bounds because numel(a)=4.

Error in accumYears (line 9) a(i) = a(i) + 5000;

As a side note, the sum as output was placed there by default for the course and it seems to be during a week where the profs were tired of students hacking the test suites so a new test suit was added to detect cheating.

code

function cost = accumYears(x)
for i = 1:x
[q, r] = quorem(i,sym(2));
if r == 0
a(i) = 2000;
end
[q, r] = quorem(i,sym(5));
if r == 0
a(i) = a(i) + 5000;
end
[q, r] = quorem(i,sym(7));
if r == 0
a(i) = a(i) + 11300;
end 
end
cost = sum(a);
end