Introduction - If you have any usage issues, please Google them yourself
(1) write a final parameters of type M, including a number of the exchange frequency, to detect the number of attributes, and rewrite the constructor and the toString method. (2) to write an abstract class A, including the sort of data. Final offers three methods, respectively compared to detection, the exchange operation at the same time, the right to change the private members of M-type object associated attributes. And to provide a virtual method doSort, while providing a final way to sort (first set the initial value M object, and then call doSort methods, the return of M object reference) (3) to write three different methods to sort the A class derived class A1, A2 , A3 (4) write a test class as the main categories, and to generate A1, A2, A3 of the object and call sort method, showed that the three methods in order when the performance parameters.