Ruby Methods

def method_name # define method
  # code
end
def greet(name) # method with parameter
  puts "Hello, #{name}"
end

def add(a, b) # method with return
  return a + b # explicit return
end
def multiply(a, b)
  a * b # implicit return (last line)
end

def greet(name = "Guest") # default value
  puts "Hello, #{name}"
end
greet # uses default "Guest"
greet("John") # uses "John"

def sum(*numbers) # accept any number of args
  numbers.reduce(0, :+) # sum all numbers
end
sum(1, 2, 3) # returns 6

def create_user(name:, age:, city: "NYC") # keyword args
  puts "#{name}, #{age}, #{city}"
end
create_user(name: "John", age: 30) # use keywords