Question

26.5 Project 3: List & Queue ADT

Overview

For this project, you are to implement two abstract data types (ADTs). You will write a doubly linked list (Dll) and a queue class. The queue will use the dll internally. The class interfaces are downloadable below. You must follow the interface exactly. While you can define other public and private methods and fields, the class names and methods given must appear as provided, or you will not pass the unit tests. Include the implementation of the classes in their respective header (.h) files. Please note: Dll is not a node class, as in, a Dll does not point to another Dll; it contains nodes internally.

Dll Comments

When inserting into a dll, rank 0 inserts at the front of the list and rank size() inserts at the back of the list. If you have the list 0 -> 10 -> 30, then after insert(2, 20), the list should be 0 -> 10 -> 20 -> 30.

When removing from a dll, rank 0 removes from the front of the list and rank size() - 1 removes from the back of the list. If you have the list 0 -> 10 -> 20 -> 30, then after remove(2), the list should be 0 -> 10 -> 30.

When building a dll from an array, the array [ 0 1 2 ] should create the list 0 -> 1 -> 2.

Displaying

When displaying a Dll, it should appear with the head on the left and the tail on the right. For example, the list created after insert(0, 3), insert(0, 2), insert(0, 1) should represent the list 1 -> 2 -> 3 and should display as follows:

[ 1 2 3 ]

When displaying a queue, it should appear with the front on the left and the back on the right. For example, the queue created after enqueue(1), enqueue(2), enqueue(3) should display as follows:

[ 1 2 3 ]

When displaying an empty ADT, it should be a single space surrounded by brackets:

[ ]

Efficiency

All operations should have an efficient runtime. Besides display(), all queue operations should run in O(1). Because the queue uses a dll internally, this means insert(), remove(), and size() must be O(1) for the appropriate cases (insert back, remove front), which also means size should be stored and not calculated by looping through the list.

Exceptions

Two exception classes can be found in exceptions.h: InvalidOperationException and IndexOutOfRangeException. Your ADTs will throw exceptions according to the instructions below:

• List: throw IndexOutOfRangeException for the following operations:
  • at(): when accessing an index outside the bounds (0 to size-1 inclusive) of the linked list with the message "at(): Index was outside the bounds of the linked list."
  • insert(): when index is not in the range from 0 to size (inclusive) with the message "insert(): Index was outside the bounds of the linked list."
  • remove(): when removing an index outside the bounds (0 to size-1 inclusive) of the linked list with the message "remove(): Index was outside the bounds of the linked list."
• Queue: throw InvalidOperationException with the message "Queue empty." when dequeuing or peeking an empty queue.

p3.cpp

p3.cpp is a command-line interface that can be used to test your data structures. Review the code before running it and testing your data structures. p3.cpp assumes your dll.h and queue.h are completed. You must comment out the portions of the code that you have not implemented (includes and the loops in main pertaining to the data structure) or create "empty" method definitions to make it compilable.

You can compile your program with g++ p3.cpp.

Notes

• Your data structures will be unit tested separately, meaning Dll can be tested accurately without a fully implemented Queue.
• Be sure to print to the ostream os variable and not to cout or you will fail the test cases.
• Throw the exceptions if the index is negative.
• Be sure to initialize pointers to NULL or nullptr as *nix environments do not initialize variables to 0.

Answer 1

in queue class four function are mentioned

1. insert ----> insert element at first of the queue.
2. remove -----> remove element from last of the queue
3. insertat------> insert element at the given position of the queue.
4. removeat--------> remove element from the given position of the queue.

#include <iostream>
#define MAX 100
using namespace std;

class Queue
{
      int front,rear;
      int queue[MAX];
 
      public:
  
      Queue()
      {
              front=rear=-1;
      }
 
       void insert(int item)
       {
              if(rear==MAX-1)
             {
                      cout<<"\nqueue overflow occured";
             }
             else if(front==-1 && rear==-1)
             {
                      front=rear=0;
                      queue[rear]=item;
                      cout<<"\n elements inserted "<<item;
             }
             else
             {
                      rear++;
                      queue[rear]=item;
                      cout<<"\nelements inserted : "<<item;
             }
       }
       void insertat(int pos,int val)
       {
       rear++;
       for(int i=rear;i>pos;i--)
       queue[i]=queue[i-1];
       queue[pos]=val;
       }
       void removeat(int pos)
       {
       for(int i=pos;i<rear;i++)
       queue[i]=queue[i+1];
       rear--;
       }
       void remove()
       {
              int item;
  
              if(rear==-1)
             {
                       cout<<"\nQueue Uderflow ";
             }
             else if(front==0 && rear==0)
             {
                       item=queue[front];
                       front=rear=-1;
                       cout<<"\n\nItems deleted : "<<item;
             }
             else
             {
                      item=queue[front];
                      front++;
                      cout<<"\n\nITEM DELETED: "<<item;
             }
       }
 
       void display()
       {
              if(front==-1)
              {
                      cout<<"\n\nQueue is Empty\n";
              }
              else
              {
                      cout<<"\n\nqueue contains element is : \n";
                      for(int i=front;i<=rear;i++)
                      {
                               cout<<queue[i]<<" ";
                      }
                      cout<<endl;
              }
        }
};

int main()
{
      Queue q;
 
      q.display();
      q.insert(10);
      q.insert(20);
       q.insert(30);
      q.insert(40);
       q.insert(50);
      q.insert(60);
       q.insert(70);
      q.insert(80);
      q.insertat(2,100);
      q.display();
      q.removeat(5);
      q.display();
      q.remove();
      q.insert(30);
 
      q.display();
      return 0;
}

output screen accrording to operation performed