   Are there some good code sample?
  I am good at architect of software(relative to arithmetic) I found I need to do arithmetic exercise. Who know good stuff. for example: give me a subject ,and give some code as answer for reference.   
  Well i'm afraid people arn't going to hang around and simply guess what you want to know.If you want to know how a common equation works then there are no better places to look than here and here. Otherwise you are going to have to be far more specific with your questions.You should really be doing three things before you ask anything,- Google- Wikipedia and similar resources (Encarta etc)- Forum searchHope that helps,Dave   ;  I want arithmetic exercise. for example:given 1,2,3....n ,solve the sum of 1+2+3....+n then give a example code for it.I just want programming exercise. Just at scholl, give some question and let you try to solve ,and finally you could see reference answer to see if your solution is right.   ;  Perhaps you could try looking in some math or computer science textbooks? Textbooks for data structures and algorithms might be good. Also Donald Knuth's books have some excercises in them, ranging from the trivial to the almost-unsolvable (the first book asks the reader to solve Fermat's Last Theorem -- I almost sure I spelled that entirely wrong -- which until a couple years ago had never been solved completely).   ;  Create a function that returns a prime number.ie int x = FindPrime(4);x should return seven because it is the fourth prime number: 2,3,5,7.  If you want to consider 1 as a prime number then your function would return five instead.   ;  There are many good exercises here. You need to register to see the problems. Most of them are fairly trivial, but there are a few difficult ones in there too.EDIT: Correction: You don't need to register to see the problems, but if you register you can submit your solutions for verification and then access a forum where people discuss their solutions. It's a lot of fun!   ;  Implement the Doomsday Algorithm (a.k.a. the Doomsday Rule).   ;TC Arena