Hi; What is wrong in my code

If we list all the natural numbers up to 15 that are multiples of 3 or 5, we get 3, 5, 6, 9, 10, 12 and 15. The sum of these multiples is 60. Write a function called sum3and5muls that returns the sum of all the unique multiples of 3 or 5 up to n where n is a positive integer and the only input argument of the function. (Credit: Project Euler)

My answer is;

function sumof = sum3and5muls(n)
 sumof = sum([3:3:n])+sum([5:5:n])-sum([15:15:n]);

Fault; Problem 8 (sum3and5muls): Testing with argument(s) 1 Feedback: Your program made an error for argument(s) 1

    Your solution is _not_ correct.

What is wrong in my code?

[SULE SAHIN]

Okey . this is acceptable

[Birdman]

There is nothing wrong with the code, it works well. How do you call the function in command line?

[Stephen23]

@SULE SAHIN: you do not need to use square brackets, because you are not concatenating anything. Instead of this sum([3:3:n]) you simply need this sum(3:3:n).

[Walter Roberson]

Please do not close questions that have an answer.

Answer 1

[Jan]

The error message tells you, that the output for n=1 differs from the expectations. Look what your code does in this case. What is 3:3:n then? What is its sum?

What happens for n=3?

3:3:n
5:5:n
15:15:n

What might be the result of:

3 + [] - []

???

Note: 3:3:n is a vector already. There is no need fro additional square brackets, see http://www.mathworks.com/matlabcentral/answers/35676-why-not-use-square-brackets