Writing good programs

Comments

A comment is any piece of text that starts with the # symbol. These are ignored by Ruby, so you can use it to write comments for yourself. For example:


#!/usr/bin/ruby

# Find the largest power of 2 
# less than 10_000
number = 1
while number < 10_000
    number *= 2
end

Notice how the comment is simply a note that you make to yourself. Simply to help you remember what your code does.

How to use comments:

Write clear comments for every step of your program.
Explain what your code does, not how it does it. If the how is not evident from the comment, then you have to fix your code.
When in doubt, write more comments, not less.

Indentation

Always indent your code. This is one of the most fundamental parts of good programming.

If you don't, your code will be illegible and you'll never manage to write anything but the simplest programs.

Good

Bad


# Add odd numbers
num, sum = 1, 0
while num < 100
    # % is remainder
    if num % 2 == 1
        sum += num
    end
    puts sum
end


# Add odd numbers
num, sum = 1, 0
while num < 100
# % is remainder
if num % 2 == 1
sum += num
end
puts sum
end

There are two identation standards. Either 4 spaces or 8 spaces. I like 4 spaces, but it's up to you.

While loops

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