Keeping it Small and Simple


Why I keep stressing students to write more code

Filed under: Ruby Programming — Tags: , , , — Lorenzo E. Danielsson @ 21:08

One thing I always tell my students is that if they really want to become good at programming they have to write a lot of code. They shouldn’t just work on projects but also create a separate directory dedicated to little experimental code snippets.

When somebody asks me if “such and such” works, I normally tell them to go and write some code to test it. I usually refuse to answer such questions until I can see some code. Needless to say, many of my students over the years have felt that I’m a royal pain in the ass.

Today I gave one of my Ruby students a little challenge: to extend Ruby’s Array class with methods to rotate the array left and right. The ROL and ROR methods should be familiar to every programmer unless, of course, you fell asleep during assembly language class. In this case we’re not even rotating bits in a byte but elements of an array.

At the end of the day, my student told me that he’ll present his solution tomorrow. I think he’s got it mostly figured out but he’s over-complicating it. This student is at the stage where he has a firm grasp of the basic elements of Ruby. But he needs to learn how to combine the facilities that the language gives him in different ways to produce the results he wants.

I’ve come to realize that this is the most difficult part of learning how to program, and the time when most students risk giving up. I guess it’s a bit similar to learning how to speak a new language. It’s fairly simple to learn the formal grammar of a language and to pick up a basic vocabulary of common, every-day expressions.

But, to combine these building blocks into more interesting sentences is challenging. I often fumble on sentences in Ga where I know all the individual words I need to use, but somehow fail to combine them in a way where I can make myself understood. The solution is simple: I have to force myself to go out and listen to and speak Ga much more. Most importantly, I have to practice the basic constructs of the language until I can use them “without” thinking.

Exactly the same thing goes with writing code. The syntax of the language and other basic elements (the most commonly used classes in Ruby’s core classes) need to be practiced until the student “becomes fluent” in using them.

So I keep on forcing my students to write loads and loads of small, trivial programs. It gets very boring for them from time to time, and I’m sure some of them would love to run me over with a freight train or something like that. But, at end my responsibility is to turn them into programmers, not win popularity contests. And I do feel that that the extra time spent on programming basics pays of for them at a later stage.

If you are a struggling with learning how to program, don’t give up. Give yourself little challenges every day. Don’t tell me you can’t think of any, because their are loads of them around you. They don’t have to be “useful” (whatever that means), and it’s okay to reinvent the wheel over and over again while you are learning.

Back to our rotating array. Anybody who has not only used, but has understood what the following methods do won’t have any problems implementing it.

  • Array#shift
  • Array#<<
  • Array#unshift
  • Array#pop

Of course there are other ways of solving it, but I’m allergic to solutions that are more complex than they need to be. It gives me a bad rash.

 1 #! /usr/bin/ruby
 3 # Rotate an array.
 5 class Array
 6   def rol!(n=1)
 7     n.times { self << self.shift }
 8   end
10   def ror!(n=1)
11     n.times { self.unshift self.pop }
12   end
13 end
15 wd = %w[Monday Tuesday Wednesday Thursday Friday Saturday Sunday]
16 puts "Original array:"
17 p wd
19 puts "Rotating right 3 times."
20 wd.ror! 3
21 p wd
23 puts "Rotating left once."
24 wd.rol!
25 p wd
27 puts "Rotating left nine times (should be like rotating left twice)."
28 wd.rol! 9
29 p wd

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