Without using any std function templates, write a function to compare two lists of equal length, returning true if every integer in the first list is the negation of the corresponding element in the second list. For example, if the two lists contained [21, 0 -4] and [-21, 0, 4], the result would be true.

bool negationOf (const list& L1, const list& L2); 

Please code in C++, nothing else. Thank You.