Question

Question 1 Continues

*** This is the NODE ADT you need. I hope this will help to solve question 1.

3) node.py :-

# CMPT 145: Node-based structures
# Defines the Node ADT
#
# A node is a simple container with two pieces of information
#   data: the contained information
#   next: a reference to another node
# We can create node-chains of any size.

# Implementation notes:
#   - uses a Python dictionary as a record.
#   - causes Assertion error if get/set called with node=None

def create(data, next=None):
    """
    Create a new node for the given data.
    Pre-conditions:
        data: Any data value to be stored in the node
        next: Another node (or None, by default)
    Post-condition:
        none
    Return:
        the node created
    """
    return {'data':data, 'next':next}

def get_data(node):
    """
    Retrieve the contents of the data field.
    Pre-conditions:
        node: a node created by create()
    Post-conditions:
        none
    Return
        the data value stored previously in the node
    """
    assert node is not None, "get_data() called with argument None"
    return node['data']

def get_next(node):
    """
    Retrieve the contents of the next field.
    Pre-conditions:
        node: a node created by create()
    Post-conditions:
        none
    Return
        the value stored previously in the next field
    """
    assert node is not None, "get_next() called with argument None"
    return node['next']

def set_data(node, val):
    """
    Set the contents of the data field to val.
    Pre-conditions:
        node: a node created by create()
        val: a data value to be stored
    Post-conditions:
        stores the new data value, replacing the existing value
    Return
        none
    """
    assert node is not None, "set_data() called with argument None"
    node['data'] = val

def set_next(node, val):
    """
    Set the contents of the next field to val.
    Pre-conditions:
        node: a node created by create()
        val: a node, or the value None
    Post-conditions:
        stores the new next value, replacing the existing value
    Return
        none
    """
    assert node is not None, "set_next() called with argument None"
    node['next'] = val

Answer 1

I am not able to get what are you trying to ask, the program given by you is correct and need no modification What's your question?

Below is the Python code I hope that i have provided sufficient comments for your better understanding Note that I have done proper indentation but this code is automatically left alligned on this interface

def create(data, next=None):
    return {'data':data, 'next':next}

def get_data(node):
    assert node is not None, "get_data() called with argument None"
    return node['data']

def get_next(node):
    assert node is not None, "get_next() called with argument None"
    return node['next']

def set_data(node, val):
    assert node is not None, "set_data() called with argument None"
    node['data'] = val

def set_next(node, val):
    assert node is not None, "set_next() called with argument None"
    node['next'] = val

I have tried to explain it in very simple language and I hope that i have answered your question satisfactorily.Leave doubts in comment section if any.