good point

Does not compile even with solution. C++

ok

Where does it say i have to return -2 if k and n are equal?

Please fix the c version

Its in C

Getting a 0 as Input

If the string isn't contained in any of the strings in the array, not only do you have to add "None" but the pResultCounter has to be increased. This is also not in the description

you also have to increase the counter, even if there is no match.

The optional parameter was not really clarified but yea that was it...

Please fix
The testcase is causing an error:

STDERR:

main.cpp:85:18: error: no matching function for call to 'orArrays'
Assert::That(orArrays(V{1,2,3},V{1,2,3},3), Equals(V{1,2,3}));
^~~~~~~~
main.cpp:7:18: note: candidate function not viable: requires 2 arguments, but 3 were provided
std::vector orArrays(const std::vector& arr1, const std::vector& arr2){
^
main.cpp:97:22: error: no matching function for call to 'orArrays'
Assert::That(orArrays(arr1, arr2, def), Equals(sol(arr1, arr2, def)));
^~~~~~~~
main.cpp:7:18: note: candidate function not viable: requires 2 arguments, but 3 were provided
std::vector orArrays(const std::vector& arr1, const std::vector& arr2){
^
2 errors generated.