Step by Step solution about How to resolve the algorithm Exceptions/Catch an exception thrown in a nested call step by step in the Ruby programming language

Overview:

The provided Ruby code defines three methods: foo, bar, and baz. It simulates an exception handling scenario where various exceptions are raised and caught.

Explanation:

1. foo Method:

   • The foo method executes a block of code twice, using the times method.
   • Inside the block, it calls the bar method and handles any exception raised by bar using a begin...rescue statement.
   • If an exception of type U0 is raised, it prints "captured exception U0" to the standard error output.

2. bar Method:

   • The bar method calls the baz method.

3. baz Method:

   • The baz method raises different exceptions based on the value of its argument i:
     • If i is 0, it raises an exception of type U0.
     • If i is not 0, it raises an exception of type U1.

4. Exception Classes:

   • Two custom exception classes, U0 and U1, are defined as subclasses of StandardError.

5. Calling foo Method:

   • Finally, the foo method is called, which will execute the block of code twice, simulating an exception handling scenario.

Execution Flow:

1. The foo method is called.
2. It executes the block of code twice with i set to 0 and 1.
3. When i is 0, the baz method raises a U0 exception, which is caught by the rescue block in foo.
4. The message "captured exception U0" is printed to standard error.
5. When i is 1, the baz method raises a U1 exception, which is not caught by foo. The exception propagates up the call stack, causing an unhandled exception.

def foo
  2.times do |i|
    begin
      bar(i)
    rescue U0
      $stderr.puts "captured exception U0"
    end
  end
end

def bar(i)
  baz(i)
end

def baz(i)
  raise i == 0 ? U0 : U1
end

class U0 < StandardError; end

class U1 < StandardError; end

foo