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Jean Malan
10,781 PointsRuby problem not compiling properly!
Hey guys!
Im suppose to run this code where the user gets a prompt to input the rover position (which will be 0,0) and then a set of instructions to manoeuvre the rover which will be: up 5, down 3, left 3, right 2, up 2, left 1. This is then stored in an array like:
[“UP 5”, “DOWN 3”, “LEFT 3”, “RIGHT 2”, “UP 2”, “LEFT 1”]
However the output I receive is x = 0, y =1 but it should be x = 0, y = 4. I have no idea where the equation is going wrong?! Any help please :)
class MarsRover
attr_accessor :position,:behaviour,:x,:y
end
# input x & y positions
def rover_position
@position = {}
puts "\nPlease input the first rover's X position: "
@position["x"] = gets.chomp.to_i
puts "\nPlease input the first rover's Y position: "
@position["y"] = gets.chomp.to_i
end
def rover_behaviour
puts " \n Please input the behaviour of the first rover (eg: Down 1, Up 2, Left 1, Right 3): "
input = gets.chomp.upcase
@behaviour = input.split(', ')
@behaviour.each do |behavior|
case behavior
when 'DOWN 1', 'DOWN 2', 'DOWN 3', 'DOWN 4', 'DOWN 5', 'DOWN 6', 'DOWN 7',
'DOWN 8', 'DOWN 9', 'DOWN 10'
move_down
when 'UP 1', 'UP 2', 'UP 3', 'UP 4', 'UP 5', 'UP 6', 'UP 7', 'UP 8',
'UP 9', 'UP 10'
move_up
when 'LEFT 1', 'LEFT 2', 'LEFT 3', 'LEFT 4', 'LEFT 5', 'LEFT 6', 'LEFT 7',
'LEFT 8', 'LEFT 9', 'LEFT 10'
move_left
when 'RIGHT 1', 'RIGHT 2', 'RIGHT 3', 'RIGHT 4', 'RIGHT 5', 'RIGHT 6',
'RIGHT 7', 'RIGHT 8', 'RIGHT 9', 'RIGHT 10'
move_right
end
end
end
# move rover left as per behaviour input
def move_down
case
when
@behaviour.include?('DOWN 1')
@position["y"] -= 1
when
@behaviour.include?('DOWN 2')
@position["y"] -= 2
when
@behaviour.include?('DOWN 3')
@position["y"] -= 3
when
@behaviour.include?('DOWN 4')
@position["y"] -= 4
when
@behaviour.include?('DOWN 5')
@position["y"] -= 5
when
@behaviour.include?('DOWN 6')
@position["y"] -= 6
when
@behaviour.include?('DOWN 7')
@position["y"] -= 7
when
@behaviour.include?('DOWN 8')
@position["y"] -= 8
when
@behaviour.include?('DOWN 9')
@position["y"] -= 9
when
@behaviour.include?('DOWN 10')
@position["y"] -= 10
end
end
def move_up
case
when
@behaviour.include?('UP 1')
@position["y"] += 1
when
@behaviour.include?('UP 2')
@position["y"] += 2
when
@behaviour.include?('UP 3')
@position["y"] += 3
when
@behaviour.include?('UP 4')
@position["y"] += 4
when
@behaviour.include?('UP 5')
@position["y"] += 5
when
@behaviour.include?('UP 6')
@position["y"] += 6
when
@behaviour.include?('UP 7')
@position["y"] += 7
when
@behaviour.include?('UP 8')
@position["y"] += 8
when
@behaviour.include?('UP 9')
@position["y"] += 9
when
@behaviour.include?('UP 10')
@position["y"] += 10
end
end
def move_right
case when
@behaviour.include?('RIGHT 1')
@position["x"] += 1
when
@behaviour.include?('RIGHT 2')
@position["x"] += 2
when
@behaviour.include?('RIGHT 3')
@position["x"] += 3
when
@behaviour.include?('RIGHT 4')
@position["x"] += 4
when
@behaviour.include?('RIGHT 5')
@position["x"] += 5
when
@behaviour.include?('RIGHT 6')
@position["x"] += 6
when
@behaviour.include?('RIGHT 7')
@position["x"] += 7
when
@behaviour.include?('RIGHT 8')
@position["x"] += 8
when
@behaviour.include?('RIGHT 9')
@position["x"] += 9
when
@behaviour.include?('RIGHT 10')
@position["x"] += 10
end
end
def move_left
case when
@behaviour.include?('LEFT 1')
@position["x"] -= 1
when
@behaviour.include?('LEFT 2')
@position["x"] -= 2
when
@behaviour.include?('LEFT 3')
@position["x"] -= 3
when
@behaviour.include?('LEFT 4')
@position["x"] -= 4
when
@behaviour.include?('LEFT 5')
@position["x"] -= 5
when
@behaviour.include?('LEFT 6')
@position["x"] -= 6
when
@behaviour.include?('LEFT 7')
@position["x"] -= 7
when
@behaviour.include?('LEFT 8')
@position["x"] -= 8
when
@behaviour.include?('LEFT 9')
@position["x"] -= 9
when
@behaviour.include?('LEFT 10')
@position["x"] -= 10
end
end
def final_position()
seporator2 = "\n"
seporator = "-"
seporator2 = "\n"
puts seporator * 80
puts seporator2
puts "\n The position of the first rover is #{@position} \n"
puts seporator * 80
puts seporator2
end
print rover_position
print rover_behaviour
print final_position
run_rover1 = MarsRover.new
1 Answer
Jack Foo
2,728 PointsHi, would like to answer your question.
From the method rover_behavior you have an iteration of @behavior.each do |behavior| block, and inside the block you are calling the method move_up/down/left/right depending on the variable |behavior| which is the element inside the @behavior array, but when you call the method move_up/down/left/right, you are calling @behavior.include? which is checking for the whole array (not the element).
So at rover_behavior you are checking for @behavior array element; and at move_up/down/left/right you are checking for @behavior the whole array.
Therefore even though in the method_behavior @behavior.each do block you are iterating the variable |behavior| "left 3", but when calling the method move_left it will still run @position['x'] -= 1 because it will check if @behavior includes "left 1" first, so ignoring the "left 3".
Use this instead:
def rover_behaviour
puts " \nPlease input the behaviour of the first rover (eg: Down 1, Up 2, Left 1, Right 3): "
input = gets.chomp.upcase
@behaviour = input.split(', ')
@behaviour.each do |behavior|
direction, movement = behavior.split(" ")
movement = movement.to_i
case direction
when 'DOWN'
@position["y"] -= movement
when 'UP'
@position["y"] += movement
when 'LEFT'
@position["x"] -= movement
when 'RIGHT'
@position["x"] += movement
end
end
end
By the way you are not using the class and defining class methods & instance variables correctly, I suggest you can revisit the course and learn more about how to properly define class and use it.
Hope you find the above useful.