static int compare(const E *x, const E *y, size_t n);
The static member function compares the sequence of length n beginning at x to the sequence of the same length 
beginning at y. The function returns:
- A negative value if the first differing element in x(as determined byeq) compares less than the corresponding 
element iny(as determined bylt).
- Zero if the two compare equal element by element. 
- A positive value otherwise.