Ruby Exceptions Initialize Error - ruby

Question

I have to create a program where I have to ask the user for their first and last name on a single line. If the user puts only their first OR last name, it will be rejected through the exception. I keep getting an error at the end (below).
class MyNewException < Exception
attr_accessor :first, :last
def initialize (first, last)
#first = first
#last = last
end
end
print "Enter your first and last name:"
begin
first, last = gets.chomp.split
print "Hello," + first + " " + last + "!"
if last.size == 0
raise MyNewException, "Sorry, I didn't catch that! Try again:"
end
rescue MyNewException
puts "Sorry, I didn't catch that. Try again:"
retry
end
Keep getting an error:
testing.rb:15:in `+': no implicit conversion of nil into String (TypeError)

Answer 1

The raise() docs are faulty. You can do this:
puts "Enter your first and last name:"
name = gets.chomp
class MyNewException < Exception
def initialize(str)
super(str) #pass the value for the message property to the parent class
end
end
begin
raise MyNewException, "Sorry, I didn't quite catch that! Try again:"
rescue MyNewException => e
puts e.message
end
--output:--
Enter your first and last name:
Sarah Kim
Sorry, I didn't quite catch that! Try again:
Or:
puts "Enter your first and last name:"
name = gets.chomp
class MyNewException < Exception
attr_accessor :first, :last
def initialize(user_name, exception_message)
#first, #last = user_name.split
super exception_message
end
end
begin
raise MyNewException.new(name, "I didn't quite catch that! Try again:")
rescue MyNewException => e
puts e.message
puts e.first
puts e.last
end
--output:--
Enter your first and last name:
Sarah Kim
I didn't quite catch that! Try again:
Sarah
Kim
Here's how to write an infinite loop to get user input:
class Person
attr_accessor :first, :last
def initialize(first, last)
#first = first.capitalize
#last = last.capitalize
end
end
while true
puts "Enter your first and last name:"
first, last = gets.chomp.split
#Show what you got:
p first
p last
if first and last
#If no names were entered, both first and last will be nil.
#If one name was entered, first will evaluate to true and last will be nil.
#If two names were entered, first and last will evaluate to true.
#If two or more names were entered, first and last will evaluate to true.
user = Person.new first, last
break #jump to the line immediately after the infinite loop
end
puts "Sorry, you must enter both a first and a last name. Try again"
end
puts "Thanks #{user.first} #{user.last}!"

Answer 2

Create a loop that do your trial and error.
as for my answer I choose while loop
i = 0
while i < 1 do
if condition == true
# display your greetings then increment loop to end
i += 1
else
# display error message
end
end
So your code would be like this
class MyNewException < Exception
attr_accessor :first, :last, :valid
def initialize(first, last)
#first = first
#last = last
#valid = true
if first.empty? || last.empty? then
#valid = false
end
end
end
i = 0
while i < 1 do
print "Enter your first name: "
firstname = gets.chomp
print "Enter your last name: "
lastname = gets.chomp
name = MyNewException.new(firstname, lastname)
if name.valid then
puts "Greetings " << name.first << " " << name.last
i += 1
else
puts "I didn't quite catch that! Try again:"
end
end