01-Ruby/01-Programming Basics

date.rb

require 'date'

# A method that receives two integers
# and returns the one that's greater

def max(x, y)
  # compare x with y
  # if x is greater
  if x > y
    # return x
    return x
  # otherwise
  else
    # return y
    return y
  end
end

puts max(3, 5)
puts max(909094534, 32312)

first_number = 7
second_number = 3
puts max(first_number, second_number)

def tomorrow
  tomorrow_date = Date.today + 1
end

puts tomorrow

hello.rb

# "Good morning".class => String
# true.class => TrueClass (Boolean)
# false.class => FalseClass (Boolean)
# 5.class => Integer
# 3.14 => Float
# ["Hello", 3, true, 3.14].class => Array
# (1..10).class
# nil.class => NilClass

# String Interpolation
# must use DOUBLE QUOTES
# "Hello, #{'world'.upcase}"

# String concatenation
# 'Hello' + ' ' + 'World' => 'Hello World'

puts "Hello, World!"


# Array of Strings
# %w[Zoe Susan John Alex]

methods.rb

# Defining methods
# Methods are like recipes
# They are a set of instructions
# def say_hello
#   return "Hello, world!"
# end # => Returns nil (because of puts)

# Let's prepare the 'meal'
# puts say_hello # call the method

# "Hello, Rui"
# Method Arguments are like recipe ingredients
def say_hello(name)
  "Hello, #{name}"
end

# "John" is a parameter
# that will be captured
# inside the methed in name
name = "Mike"

puts say_hello("John")
puts say_hello("Gus")
puts say_hello(name)

puts "End!"

variables.rb

age = 17 # declaring and assigning

# String concatenation
# puts "The value of age is: " + age.to_s

# String Interpolation
puts "The value of age is: #{age}"

puts "It's your birthday today!"

#      17 + 1 => 18
age = age + 1 # Reassigning
puts "Age is now: #{age}"
# shorthand syntax
age += 1 # equivalent to age = age + 1
puts "Age is now: #{age}"

# firstName => Camel case (JavaScript)
# FirstName => Upper Camel case (Class names)
# first_name => snake_case (variables, method names and filenames)
first_name = "rui"
puts "My name is #{first_name.capitalize}"

names = ["John", "Susan", "Abe", "Michael"]
puts names.class