Andrey Drozdov - 8 months ago 17

Ruby Question

It's my second question about creating geometric shapes via classes.

So, I want to create a circle.

- First of all I create a class Point
- Then - create a class Line, using two points (this will be our diameter)
- Now we have to calculate the distance between this points (diameter)
- Then we create class Circle
- And using diameter to create a circle

Hope, so far so good. But when i get to coding i meat some troubles.

Creating class Point:

`class Point`

attr_accessor :x, :y

def initialize

@x = 10

@y = 10

end

end

Then, class Line:

`class Line`

attr_accessor :p1, :p2

def initialize

@p1 = Point.new

@p2 = Point.new

end

def distance

@distance = Math::sqrt((@p2.x - @p1.x) ** 2 + (@p2.y - @p1.y) ** 2) # -> rb.16

end

end

And in Line class the problems starts. As you understand I want to define method to calculate distance between points in the Line class. Thnx to google search the formula for calculating is:

square root from ((point_2.x - point_1.x)**2 + (point_2.y - point_1.y)**2)

`#points`

point_01 = Point.new

point_01.x = 20

point_02 = Point.new

point_02.x = 10

#line

d = Line.new

d.p1 = point_01

d.p2 = point_02

dis = d.distance # -> rb.40

print dis

But it puts me an error:

`rb:16:in `distance': wrong number of arguments (1 for 0) (ArgumentError)`

rb:40: in `<top (required)>'

from -e:1:in `load'

from -e:1:in `<main>'

What are this errors, what they mean?

And the next step will be to calculate circumference (C) with formula:

C = Pi * Diameter

Is that right?

`class Circle`

attr_accessor :diametr, :c

def initialize

@diametr = Line.new

end

def circle_length

return @c = @diametr * Math::PI

end

end

#circle

circle = Circle.new

circle.diametr = d

res = circle.circle_length

Please note that I'm only studying and it may be a silly question but still I don't understand it.

Thank for your help!

Yeah, thnx to the comment below, the error appears Circle class, after using formula to calculate circumference. can you help me with this.

Answer

I ran your code and I'm not getting the `rb:16:in distance': wrong number of arguments (1 for 0) (ArgumentError)`

error.

The `circle_length`

method does throw an error and it's because you are trying to multiply `@diameter`

, which is an instance of `Line`

.

You need to implement `*`

, which is really just a method, for `Line`

:

```
class Line
def *(other)
distance * other
end
end
```