Ruby - Exceptions (rescue, raise) 2020

In this article, we'll learn how to try/catch (begin/rescue):

#!/usr/bin/ruby
# f1.rb
# How to function

def addition(n1, n2)
   return n1.to_i + n2.to_i
end

puts addition(3,9)

Output 1 :

$ ./rescue.rb
Enter a number : 10
Enter another number : 2
10/2 = 5

Output 2 :

$ ./rescue.rb
Enter a number : 9 
Enter another number : 0
Division by zero!
./rescue.rb:16:in `/': divided by 0 (ZeroDivisionError)
	from ./rescue.rb:16:in `<main>'

Now, we may want to raise:

#!/usr/bin/ruby
# raise.rb
# How to try/catch (begin/rescue/raise)

weight = 150

def check_weight(w)
   raise ArgumentError, " Enter positive number" unless w > 0
end

begin
   check_weight(-1)
rescue ArgumentError
   puts "Weight should be greater than 0"
end

Output:

$ ./raise.rb
Weight should be greater than 0