... struct Object * self = isObject(_self);const struct Class * myClass = isObject(self —> class);if (class != Object) { isObject(class);while (myClass != class){ assert(myClass != Object) ; ... _Object = {{ MAGIC, & _Class }," ;Object& quot;, & _Object, sizeof(struct Object) , Object_ ctor, Object_ dtor, Object_ differ, Object_ puto};extern introduces forward references to the descriptions. ... (contains(s, drop(s, a)))puts("drop?");delete(drop(s, b));delete(drop(s, c));return 0;}We create a set and add two new objects to it. If all is well, we find the objects inthe...