Question

class UnitCircle
    def prompt
        puts "Enter a number: "
        @number = gets
        @number = @number.to_i
        puts "Enter a trigonometric equation to perform on that number: "
        @eqn = gets
    end
end
uc = UnitCircle.new
uc.prompt
num = Math.send(uc.instance_eval {@eqn}, uc.instance_eval {@number})

When I try to run it with say,

@number = 30
@eqn = sin

I get a no method error, why?

Answer 1

class UnitCircle
    def prompt
        puts "Enter a number: "
        @number = gets.chomp
        @number = @number.to_i
        puts "Enter a trigonometric equation to perform on that number: "
        @eqn = gets.chomp
    end
end

gets method will include the new line symbol “\n”. So you have to chomp it.
If you do not chomp, you will end up calling method “sin\n” instead of “sin”