Question

Data Structures & Algorithms . Solve this problem in java(not C language) .

Question 1(Queue) Write a program that display list of choices for the user to interact with the program as follow:

Queue Operations Menu:

1.Add a new item

2.Delete the first item

3.Show number of items in the Queue

4.Find an item

5.Show all items

6.Exit

Answer 1

CODE

import java.util.*;

/* Class arrayQueue */

class arrayQueue

{

protected int Queue[] ;

protected int front, rear, size, len;

/* Constructor */

public arrayQueue(int n)

{

size = n;

len = 0;

Queue = new int[size];

front = -1;

rear = -1;

}

/* Function to check if queue is empty */

public boolean isEmpty()

{

return front == -1;

}

/* Function to check if queue is full */

public boolean isFull()

{

return front==0 && rear == size -1 ;

}

/* Function to get the size of the queue */

public int getSize()

{

return len ;

}

/* Function to check the front element of the queue */

public int peek()

{

if (isEmpty())

throw new NoSuchElementException("Underflow Exception");

return Queue[front];

}

/* Function to insert an element to the queue */

public void insert(int i)

{

if (rear == -1)

{

front = 0;

rear = 0;

Queue[rear] = i;

}

else if (rear + 1 >= size)

throw new IndexOutOfBoundsException("Overflow Exception");

else if ( rear + 1 < size)

Queue[++rear] = i;

len++ ;

}

/* Function to remove front element from the queue */

public int remove()

{

if (isEmpty())

throw new NoSuchElementException("Underflow Exception");

else

{

len-- ;

int ele = Queue[front];

if ( front == rear)

{

front = -1;

rear = -1;

}

else

front++;

return ele;

}

}

/* Function to display the status of the queue */

public void display()

{

System.out.print("\nQueue = ");

if (len == 0)

{

System.out.print("Empty\n");

return ;

}

for (int i = front; i <= rear; i++)

System.out.print(Queue[i]+" ");

System.out.println();

}

public int search(int val) {

for (int i = front; i <= rear; i++) {

if (Queue[i] == val) {

return i;

}

}

return -1;

}

}

/* Class QueueImplement */

public class QueueImplement

{

public static void main(String[] args)

{

Scanner scan = new Scanner(System.in);

System.out.println("Enter Size of Integer Queue ");

int n = scan.nextInt();

/* creating object of class arrayQueue */

arrayQueue q = new arrayQueue(n);

/* Perform Queue Operations */

char ch;

while(true) {

System.out.println("\nQueue Operations");

System.out.println("1. Add an item");

System.out.println("2. Remove the first item");

System.out.println("3. Show number of items in the Queue");

System.out.println("4. Find an item");

System.out.println("5. Show all items");

System.out.println("6. Exit");

int choice = scan.nextInt();

switch (choice)

{

case 1 :

System.out.println("Enter integer element to insert");

try

{

q.insert( scan.nextInt() );

}

catch(Exception e)

{

System.out.println("Error : " +e.getMessage());

}

break;

case 2 :

try

{

System.out.println("Removed Element = "+q.remove());

}

catch(Exception e)

{

System.out.println("Error : " +e.getMessage());

}

break;

case 3 :

System.out.println("Number of items: " + q.getSize());

break;

case 4 :

System.out.println("Enter integer element to be searched");

int pos = q.search(scan.nextInt());

if (pos != -1) {

System.out.println("Element found at position: " + pos);

} else {

System.out.println("Element not found!!");

}

break;

case 5 :

q.display();

break;

case 6 :

return;

break;

default : System.out.println("Wrong Entry \n ");

break;

}

}

}

}