Question

Python

Stack: The following was done already in the Lab in the Stacks Module with Doubly Linked List.

Create an application to help you stack and un-stack containers in the ship.

Create a class called container which will have the object (data), the link (next)

Create a class called Pod which is Stack. Include methods addContainer and removeContainer

Implement these classes by creating multiple containers to go inside the pod.

ADD the Following feature:

Include a class attribute in the container class called name.

In the implementation - Pod:

You should ask the user to enter the name of the container and the program should add the container to the Pod repeatedly.

Once done, You should ask the user which container to remove from the Pod. When the user gives the name of the container, the program should go through the Pod and remove that container alone from the Pod.

Clue: Remember if you want to remove one item from the Stack, you should use only the top to remove. So if you want to remove the fifth item from the top of the Stack, you should remove all the four items above it, remove the fifth item and then put back all the four items in the same order.

Write a method called removeNamedContainer in Pod program for implementing the above.

Answer 1

# container class containing data and next attributes

class container():

def __init__(self,data):

self.data=data

self.next=None

# pod class containing addcontainer and removecontainer methods

class pod():

# addcontainer

def addContainer(self,head,containerObj):

# check if intial container exists to stack contianers

if(head):

temp = head

while(temp.next):

temp=temp.next

temp.next=containerObj

return head

else:

return containerObj

# removecotainer

def removeContainer(self,head):

# removing container in stack manner such that the container which is on top

# removed first

if(head.next):

temp = head

prev = None

while(temp.next):

prev=temp

temp=temp.next

prev.next=None

return head

else:

return None

# method to list all the available containers and ships

def helper(head):

while(head):

print(head.data)

head=head.next

print("working with container and pod")

# containers

container_one = container("container_1")

container_two = container("container_2")

container_three = container("container_3")

container_four = container("container_4")

# pod object

podObj = pod()

# adding containers to pod

head = podObj.addContainer(None,container_one)

head = podObj.addContainer(head,container_two)

head = podObj.addContainer(head,container_three)

head = podObj.addContainer(head,container_four)

# listing all the containeer availabl to cross check

print("ALl the added containeers")

helper(head)

# removind containers from stack so it results in removing

# container_4 and container_3

head = podObj.removeContainer(head)

head = podObj.removeContainer(head)

# listing all the containeer availabl to cross check

print("left over containeers after removing few in stack manner(LIFO)")

helper(head)

# ship class containing data and next attributes

class ship():

def __init__(self,data):

self.data=data

self.next=None

class Port():

# adding ships to dock

def dock(self,head,shipObj):

if(head):

temp=head

while(temp.next):

temp=temp.next

temp.next=shipObj

return head

else:

return shipObj

# undocking ships in first come first out manner

def undock(self,head):

if(head):

temp = head.next

head.next=None

head=temp

return head

else:

return None

print("working with ship and Port")

# ships

ship_one = ship("ship_1")

ship_two = ship("ship_2")

ship_three = ship("ship_3")

ship_four = ship("ship_4")

portObj = Port()

# dock ships

head = portObj.dock(None,ship_one)

head = portObj.dock(head,ship_two)

head = portObj.dock(head,ship_three)

head = portObj.dock(head,ship_four)

# listing all the ships available to cross check

print("All the ships available in port")

helper(head)

# undock ships from the port it results in removing

# ship_1 and ship_2 as the first ship in queue is served first

head = portObj.undock(head)

head = portObj.undock(head)

# listing all the ships available to cross check

print("All the ships available in port after undocking few in Queue manner (FIFO)")

helper(head)