Ruby common exception

1, RuntimeError
Reason: This is the default exception raised by the raise method

raise

2, NoMethodError
Reason: An object is sent a message it can't resolve to a method name

a = Object.new
a.some_unkonw_method_name

3, NameError
Reason: The interpreter hits an identifier it can't resolve as a variable or method name

a = some_random_identifier

4, IOError
Reason: This is caused by reading a closed stream, writing to a read-only stream, and similar operations

STDIN.puts("Don't write to STDIN!")

5, Errno::error
Reason: This family of errors relates to file IO

File.open(-12)

6, TypeError
Reason: A method receives an argument it can't handle

a = 3 + "can't add a string to a number!"

7, ArgumentError
Reason: This is caused by using the wrong number of arguments

def m(x); end; m(1, 2, 3, 4, 5)