# 01 - catch a  general error

def do_something(thing):
    x = 0
    try:
        x = 1
        print 'Hello' + thing
        x = 2
        print x
    except:
        print x
def main():
    do_something(4)
if __name__ == '__main__':
    main()

# All the legal commands inside the 'try' block are
# executed normally. If any exception is raised, the
# processor jumps to the except section for that 'try'

#----------------------------------------------------------------
# 02 - catch a specific error (s) in the order written

def do_something(thing):
    x = 0
    y = 1
    try:
        y = 2
        y = y / x                 # If we comment this, falls into the next (general exception)
        print 'Hello' + thing 
        print x
    except ZeroDivisionError:
        print x, ' is zero'
    except:
        print 'Error in print'
def main():
    do_something(4)
if __name__ == '__main__':
    main()
#-----------------------------------------------------------------

# 03 - finally - do it whether or not exception had occurred
#      if the exception did not capture the error, it will still
#      execute the 'finally' clause, and then show the error

def do_something(thing):
    x = 0
    y = 1
    try:
        y = 2
        print 'Hello' + thing 
        print x
    except ZeroDivisionError:  # Only catches zero division error
        print x, ' is zero'
    finally:
        print 'The final frontier'

def main():
    do_something(4)
if __name__ == '__main__':
    main()
#----------------------------------------------------------------
# Does catch the error

def do_something(thing):
    x = 0
    y = 1
    try:
        y = 2
        print 'Hello' + thing 
        print x
    except:  
        print 'general error'
    finally:
        print 'The final frontier'

def main():
    do_something(4)
if __name__ == '__main__':
    main()
#--------------------------------------------------------------------------
# 04 - intentionally raising an error (builtin)

def do_something(thing):
    x = 0
    y = 1
    try:
        # Using builtin exception
        raise MemoryError('Total recall , you have lost your memory')
    except MemoryError as e:
        print e
    finally:
        print 'The final frontier'

def main():
    do_something(4)
if __name__ == '__main__':
    main()
#---------------------------------------------------------------------------
# 05 Define your own exception, if builtins are insufficient
# We need to create a class that inherits from Exception

class Myexception(Exception):
    def __init__(self, msg):
        self.msg = msg
    def print_exception(self):
        print 'User defined exception:', self.msg

def main():
    counter = 5
    try:
        if counter < 10:
            raise Myexception('counter must be not less than 10')
    except Myexception as e:  # Create object e from class
        e.print_exception()   # Use method on object e
    else:
        print 'no error occurred'  # if we change the 5 to 5, this prints

if __name__ == '__main__':
    main()