12. Define a function equal which takes two forward iterator pairs as arguments defining ranges and which return:s true if all elements are equal and the ranges are the same length. You may not use size () on the iterators or subtract them. Use operator- to compare elements. [3V] template bool equal (T beginl, T endl, T begin2, T end2) 13. Define the classes square and circle, both of which inherit as public from shape. For each class, also define a constructor with a default argument of 0: for a circle, the argument is its radius, and for square, then length of one edge. Assume ()) will return true if the range is increasing. It would return true for a monotonically decreasing function if passed greater bool monotonic (Itor begin, Itor end, Function fn)