Solar System

main.rb

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+require_relative 'planet'
+require_relative 'solar_system'
+
+def main
+
+  jupiter = Planet.new('Jupiter', 'brown', 4.972e24, 1.506e8, 'Only planet known how to be happy in life')
+  venus = Planet.new('Venus', 'gray', 2.972e24, 1.126e8, 'Only planet known how to travel around the world')
+  #===================
+  # create an instance of SolarSystem, add all your Planets to it
+  solar_system = SolarSystem.new('Sol')
+
+  all_planets = [jupiter, venus]
+  all_planets.each do |planet|
+    solar_system.add_planet(planet)
+  end
+
+  while true
+    puts "please select one: \n- list planets \n- planet details \n- add planet \n- enter exit to quit!"
+    print "? "
+    user_input = gets.chomp
+
+    case user_input
+
+    when "list planets"
+      puts solar_system.list_planets
+
+    when "planet details"
+      puts "which planet(name of the planet)?"
+      planet_name = gets.chomp.capitalize!
+      planet_summary = solar_system.find_planet_by_name(planet_name)
+      puts planet_summary.summary
+
+    when "add planet"
+      puts "enter the name of the planet you would like to add: "
+      name = gets.chomp.capitalize!
+      puts "color of the planet? "
+      color = gets.chomp.capitalize!
+      puts "planet's mass in kg?"
+      mass_kg = gets.chomp.to_i
+      puts "planet distance from the sun?"
+      distance_from_sun_km = gets.chomp.to_i
+      puts "a fun fact about the planet?"
+      fun_fact = gets.chomp
+      new_planet = Planet.new(name, color, mass_kg, distance_from_sun_km, fun_fact)
+      solar_system.add_planet(new_planet)
+
+    when "exit"
+      break
+    else
+      puts "wrong input"
+    end
+  end
+end
+
+
+main

planet.rb

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+class Planet
+  #info about single planet
+  def initialize(name, color, mass_kg, distance_from_sun_km, fun_fact)
+    @name = name
+    @color = color
+    @mass_kg = mass_kg
+    @distance_from_sun_km = distance_from_sun_km
+    @fun_fact = fun_fact
+  end
+
+  # readable from outside the class, but not writable.
+  attr_reader :name, :color, :mass_kg, :distance_from_sun_km, :fun_fact
+
+  def summary
+    return "#{@name} is a #{@color}. it has a mass of #{@mass_kg} - distance from sun: #{@distance_from_sun_km} - fun fact: #{@fun_fact}"
+  end
+end
+
+# earth = Planet.new('Earth', 'blue-green', 5.972e24, 1.496e8, 'Only planet known to support life')
+# puts earth.name
+# puts earth.fun_fact
+

solar_system.rb

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+require_relative 'planet'
+
+class SolarSystem
+  # constructor
+  def initialize(star_name)
+    @star_name = star_name
+    @planets = []
+  end
+
+  attr_reader :planets, :star_name
+
+  # take an instance of Planet as a parameter and add it to the list of planets.
+  def add_planet(planet)
+    @planets << planet
+  end
+
+  def list_planets
+    list_of_all_planets = "Planets orbiting #{@star_name}: \n"
+    @planets.each_with_index do |planet, i|
+      list_of_all_planets += "#{i + 1}. #{planet.name} \n"
+    end
+    return list_of_all_planets
+  end
+
+  # takes the name of a planet as a string, and returns the corresponding instance of Planet
+  def find_planet_by_name(planet_name)
+    # instance_of_planet = @planets.find { |planet| planet.name.downcase == planet.name.downcase}
+    @planets.each do |planet|
+      if planet.name == planet_name
+        return planet
+      end
+    end
+  end
+end
+