^

This is not an issue with a kata. Logging to console !== returning value from function.

In JavaScript:

console.log(arr, n) gives me:
[ 1, 2, 3, 4 ] 2

and result of my function gives:
9

what I got from the system is:
expected undefined to equal 9

Aren't we supposed to return either equation result or -1?

Nice Work!!!
Keep it up!

it's allowed to write after "return" without parentheses

Why do you need to define the argument as an empty string instead of just leaving it as name (what it was originally)?

Fixed.

in C, sample tests won't compile:

"/tmp/fixture-4fb33b.o: In function the_multiply_function_should_pass_all_the_tests_provided_impl': fixture.c:(.text+0x32): undefined reference to foo'
clang: error: linker command failed with exit code 1 (use -v to see invocation)"

Same program works when submitted.