Learn Ruby - The Hard Way

Exercise %,: 6esi!nin! and 6ebu!!in!  Fow that you !now i+-state(ents, I'm going to gi*e you some rules for +or-loops and 8/ile-loops that will !ee you out of trouble. I'm also going to gi*e you some tis on debugging so that you can figure out roblems with your rogram. :inally, you are going to design a similar little game as in the last e&ercise but with a slight twist.

R#les &or 0f-State+ents $. 0*ery i+-state(ent  must ha*e an else. . If this else should ne*er be run because it doesn't ma!e sense, then you must use a *ie function in the else that rints out an error message and dies, ust li!e we did in the last e&ercise. This will find many errors. (. Fe*er nest i+-state(ents more than  dee and always try to do them $ dee. This means if you ut an i+ in an i+ then you should be loo!ing to mo*e that second i+ into another function. B. Treat i+-state(ents li!e aragrahs, where each i+,elsif,else grouing is li!e a set of sentences. Put blan! lines before and after. C. +our boolean tests should be simle. If they are comle&, mo*e their calculations to *ariables earlier in your function and use a good name for the *ariable. If you follow these simle rules, you will start writing better code than most rogrammers. %o bac! to the last e&ercise and see if I followed all of these rules. If not, fi& it. Warnin!

 Fe*er be a sla*e to the rules in real life. :or training uroses you need to follow these rules to ma!e your mind strong, but in real life sometimes these rules are ust stuid. If you thin! a rule is stuid, try not using it.

R#les &or Loops $. Ese a 8/ile-loop only to loo fore*er, and that means robably ne*er. This only alies to Ruby, other languages are different. . Ese a +or-loop for all other !inds of looing, esecially if there is a fi&ed or limited number of things to loo o*er.

Tips &or De/#gging  $. o not use a "debugger". - debugger is li!e doing a full1body scan on a sic! erson. +ou do not get any secific useful information, and you find a whole lot of information that doesn't hel and is ust confusing. . The best way to debug a rogram is to use puts or p to rint out the *alues of *ariables at oints in the rogram to see where they go wrong. (. )a!e sure arts of your rograms wor! as you wor! on them. o not write massi*e files of code before you try to run them. ;ode a little, run a little, fi& a little.

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