Calling methods within methods ruby - ruby

Question

I'm trying to figure out how to call methods inside methods in ruby.
Here's my code:
def testNegative number
if number < 0 # No negative numbers.
return 'Please enter a number that isn\'t negative.'
end
end
def testIfZero number
if number == 0
return 'zero'
end
end
def englishNumber number
testNegative(number)
testIfZero(number)
end
puts englishNumber -1
puts englishNumber 0
Currently, the output I'm getting is an empty line and then "zero". I was wondering why I don't see "Please enter a number that isn't negative" as the output of put englishNumber -1. How can I fix things so that "Please enter a number that isn't negative" is returned and the programs ends?

Answer 1

I'll use underscores instead of camel case in my answer, because that is what people usually do for Ruby methods.
Your code doesn't work right now because test_negative is returning a value but english_number is not doing anything with the value. You could change english_number to:
def english_number(number)
test_negative(number) or test_if_zero(number)
end
That way if test_negative returns a non-nil and non-false value, then english_number will use that as its return value and not bother running test_if_zero.
Later, if you need to add more lines of code to english_number, you can do it like this:
def english_number(number)
error_message = test_negative(number) || test_if_zero(number)
return error_message if error_message
# More lines of code here
end
By the way, it sounds like you might actually want to use exceptions. When you raise an exception, the program will end and the exception message will be printed to the user unless you do something to catch and handle the exception. I would change test_negative to:
def test_negative(number)
if number < 0 # No negative numbers.
raise 'Please enter a number that isn\'t negative.'
end
end

Answer 2

Your code
def englishNumber number
testNegative(number)
testIfZero(number)
end
calls first testNegative(number) and ignores the result.
Then it calls testIfZero(number) and returns the result to the caller.
For englishNumber -1 the result of testIfZero(number)is nil and putswrites an empty line.
For englishNumber 0 you get the expected string 'zero'.
If you need a the results as alternative you must return the results with an or condition (or ||).
A complete example:
def testNegative number
if number < 0 # No negative numbers.
return 'Please enter a number that isn\'t negative.'
end
end
def testIfZero number
if number == 0
return 'zero'
end
end
def englishNumber number
testNegative(number) or testIfZero(number)
end
puts englishNumber -1
puts englishNumber 0
or with an alternate syntax:
def testNegative number
return 'Please enter a number that isn\'t negative.' if number < 0 # No negative numbers.
end
def testIfZero number
return 'zero' if number == 0
end
def englishNumber number
testNegative(number) || testIfZero(number)
end
puts englishNumber -1
puts englishNumber 0
I'm not sure if I understand your comments correct, but maybe you are looking for a solution like this:
def testNegative number
puts 'Please enter a number that isn\'t negative.' if number < 0 # No negative numbers.
end
def testIfZero number
puts 'zero' if number == 0
end
def englishNumber number
testNegative(number)
testIfZero(number)
end
englishNumber -1
englishNumber 0
The puts command can also be used inside the methods, you don't need to return a result.
Remark outside the scope of the question: The usage of a method call inside a method is not the simplest solution (but I think you want to check the usage of method calls).
I would use:
def english_number number
if number < 0 # No negative numbers.
return 'Please enter a number that isn\'t negative.'
elsif number == 0
return 'zero'
end
end