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Start your free trialErin Claudio
Courses Plus Student 8,403 PointsI think I found a bug
I received a positive grade for this code but I am not sure that is good code, please help?
def check_speed(speed)
if speed < 45
puts "too slow"
elsif speed > 55
puts "too fast"
else speed == 45..60
puts "speed OK"
end
def check_speed(speed)
if speed < 55
puts "too slow"
end
if speed > 55
puts "too fast"
end
if speed == 55
puts "speed OK"
end
end
Erin Claudio
Courses Plus Student 8,403 PointsHello Jay, or should I say Professor McGraven, I posted the incorrect code to the previous post. Below please find the code that I entered which was accepted in this code challenge which I am not sure is valid Ruby. Thank you for your help.
def check_speed(speed)
if speed < 45
puts "too slow"
elsif speed > 60
puts "too fast"
else speed = 45..60
puts "speed OK"
end
end
Jay McGavren
Treehouse TeacherErin Claudio "Jay" will do. :)
So here's what the code you posted in this latest comment looks like to Ruby:
def check_speed(speed)
if speed < 45
puts "too slow"
elsif speed > 60
puts "too fast"
else
speed = 45..60
puts "speed OK"
end
end
Let's say you made the call check_speed(55)
. 55 isn't less than 45, so the if
clause wont' run. 55 also isn't greater than 60, so the elsif
clause won't run. So the else
clause runs instead.
The first statement in the else
clause will discard the number 55
stored in speed
, and assign the Range
value 45..60
to speed
instead. Now, I'm sure this is not at all what you meant to do, but that's what is written here, so that's what Ruby does. But the code works anyway, because it never accesses the speed
variable again. It goes on to print "speed OK"
, which is what is requested in the challenge description, and is what our unit tests test for. That's why it passes.
There are two important lessons to learn here:
- Never, ever put a condition following an
else
clause.else
should always be on a line all by itself. It won't fail to compile, but it is very likely to introduce a bug. If you really want a condition, useelsif
, notelse
. - The difference between
==
(equality comparison) and=
(assignment) is very important! Again, it is very likely to introduce a bug if you make a mistake. Please review this video for details on the difference.
2 Answers
Steven Parker
231,198 PointsThe last video was about using "elsif" and "else" so you can handle more conditions with fewer tests. See if you can use those keywords here.
Hint: Once you've checked for "too high" and "too low", wouldn't everything else be "OK"?
Steven Parker
231,198 PointsOh, I see, I was looking at the color code and thinking you wanted hints to pass. Odd that it did not show what you actually entered.
Erin Claudio
Courses Plus Student 8,403 PointsI do not think I posted the question well. Below is the code I posted to the challenge which I received passing grade I think this answer is not correct
def check_speed(speed)
if speed < 45
puts "too slow"
elsif speed > 60
puts "too fast"
elsespeed == 45..60
puts "speed OK"
end
end
thank you for any help
Steven Parker
231,198 PointsIt does look like you have discovered a bug, even without formatting, that final comparison clearly does not belong (and a plain "else" does not take a condition).
You might want to submit a bug report to the staff, instructions can be found on the Support page. If you're the first (and they agree it's a bug) you should get the special "Exterminator" badge.
Jay McGavren
Treehouse TeacherThis code does not pass the challenge for me either (which is as it should be):
def check_speed(speed)
if speed < 45
puts "too slow"
elsif speed > 60
puts "too fast"
elsespeed == 45..60
puts "speed OK"
end
end
I get this error message:
We called check_speed with an argument of 45, but it didn't print "speed OK".
Again, although this code is not as intended, it's technically legal Ruby, so there's no syntax error for our challenge engine to report. To Ruby, the code looks more like this:
def check_speed(speed)
if speed < 45
puts "too slow"
elsif speed > 60
puts "too fast"
elsespeed == 45..60
puts "speed OK"
end
end
If you tried calling check_speed(61)
with the above code, you'd get the error undefined local variable or method 'elsespeed' for main:Object
. But the tests we're running behind the scenes don't get that far; they fail when they try to call check_speed(45)
.
Again, the solution is to remove that conditional from the else
clause, which shouldn't be there anyway.
Jay McGavren
Treehouse TeacherJay McGavren
Treehouse TeacherSo you're saying that you entered this code for the challenge:
...and it was accepted, and you feel it should not have been, is that right?
But when I enter the above code in the challenge, it is not accepted. I get the failure message:
And even if you add an
end
keyword on line 8, it then fails with the message:So I guess I'm not understanding the issue.
You are definitely going to want to remove the boolean clause from
else speed == 45..60
. That's technically legal Ruby, but there isn't supposed to be a condition following theelse
keyword, onlyif
andelsif
.