monkey_patching.rb

# Monkey Patching
# Monkey patching is a technique in programming where you can modify or extend the behavior of existing classes or modules at runtime (mostly use in string, array, and hash). 
# This can be useful for adding new functionality, fixing bugs, or changing the behavior of existing methods without modifying the original source code.

class String
  # Adding a new method to count the number of vowels in a string
  # self.count is a built-in method that counts the occurrences of specified characters in the string.
  # self refers to the instance of the String class on which the method is called.
  def count_vowels
    self.count('aeiouAEIOU')
  end
end

p "Hello World".count_vowels # Output: 3
test = "Monkey Patching"
p test.count_vowels # Output: 4

class Array
  # Adding a new method to check if the array is sorted?
  # self.sort is a built-in method that returns a new array with the elements sorted in ascending order.
  # self refers to the instance of the Array class on which the method is called. 
  # And self.sort is a sorted method that returns a new array with the elements sorted in ascending order.
  def sorted?
    self == self.sort
  end
end

p [1, 2, 3].sorted? # Output: true
p [3, 2, 1].sorted? # Output: false