Question

Question - Write a Client class with a main method that tests the data structures as follows:

• For the ArrayStack, LinkedStack, ArrayQueue, LinkedQueue, and ArrayList:
  • Perform a timing test for each of these data structures.
  • Each timing test should measure in nanoseconds how long it takes to add and remove N Integers from the structure.
  • N should vary from 10 to 1,000,000,000 increasing N by a factor of 10 for each test.
  • Depending on your system you may run out of memory before you reach the maximum value of N.
    • If you run out of memory, and your program crashes just decrease the maximum value of N by a factor of 10 and try a new run.
    • You should see that your program throws an OutOfMemoryError
    • Generally, you should not try to catch an Error because your memory space might be corrupted and there is not guarantee that you can recover from the error.
  • Test results must be displayed in a nicely formatted ASCII table similar to the examples provided.
  • In the ASCII table:
    • Values in each cell are padded by 2 blank spaces
    • Each column is just wide enough to display the widest entry in that column including the cell padding. Your program must dynamically adjust the width of each column based on the values that it needs to print.
    • Numeric values must be printed using the comma thousand separator, i.e.
      • you must print a large number like 12,345
      • and not 12345
    • It is strongly suggested that you create a method that generates and prints the ASCII table. You could pass this method a 2-dimensional array of values that are to be printed.
    • Future assignments may require that you print out results in a similar ASCII table.
  • You should have two final runs in your Word document.
  • For the first run set the max value of N to 1,000,000 so that the times are fairly small.
  • For the second run set the max value of N to 1,000,000,000
  • If you run out of memory reduce the max value of N by a factor of 10 and try a new run.
  • For this assignment your ASCII tables do NOT need to have column labels.
  • Include both runs in your Word document.
• ArrayStack code:

• public class ArrayStack<E> implements Stack<E> {
  public static final int CAPACITY=1000; // default array capacity
  private E[ ] data; // generic array used for storage
  private int t = -1; // index of the top element in stack
  public ArrayStack( ) { this(CAPACITY); } // constructs stack with default capacity
  public ArrayStack(int capacity) { // constructs stack with given capacity
  data = (E[ ]) new Object[capacity]; // safe cast; compiler may give warning
  }
  public int size( ) { return (t + 1); }
  public boolean isEmpty() {return (t == -1); }
  public void push(E e) throws IllegalStateException {
  if (size( ) == data.length) throw new IllegalStateException("Stack is full");
  data[++t] = e; // increment t before storing new item
  }
  public E top( ) {
  if (isEmpty( )) return null;
  return data[t];
  }
  public E pop( ) {
  if (isEmpty( )) return null;
  E answer = data[t];
  data [t] = null; // dereference to help garbage collection
  t--;
  return answer;
  }
  }

• LinkedStack code:

• public class LinkedStack<E> implements Stack<E> {
  private SinglyLinkedList<E> list = new SinglyLinkedList<>( ); // an empty list
  public LinkedStack( ) { } // new stack relies on the initially empty list
  public int size( ) { return list.size( ); }
  public boolean isEmpty( ) { return list.isEmpty( ); }
  public void push(E element) { list.addFirst(element); }
  public E top( ) { return list.first( ); }
  public E pop( ) { return list.removeFirst( ); }
  }

• ArrayQueue code:

• public class ArrayQueue<E> implements Queue<E> {
  // instance variables
  private E[ ] data; // generic array used for storage
  private int f = 0; // index of the front element
  private int sz = 0;
  private static int CAPACITY = 1000;
  // current number of elements

  // constructors
  public ArrayQueue( ) {this(CAPACITY);} // constructs queue with default capacity
  public ArrayQueue(int capacity) { // constructs queue with given capacity
  data = (E[ ]) new Object[capacity]; // safe cast; compiler may give warning
  }

  // methods
  /** Returns the number of elements in the queue. */
  public int size( ) { return sz; }

  /** Tests whether the queue is empty. */
  public boolean isEmpty( ) { return (sz == 0); }

  /** Inserts an element at the rear of the queue. */
  public void enqueue(E e) throws IllegalStateException {
  if (sz == data.length) throw new IllegalStateException("Queue is full");
  int avail = (f + sz) % data.length; // use modular arithmetic
  data[avail] = e;
  sz++;
  }

  /** Returns, but does not remove, the first element of the queue (null if empty). */
  public E first( ) {
  if (isEmpty( )) return null;
  return data[f];
  }

  /** Removes and returns the first element of the queue (null if empty). */
  public E dequeue( ) {
  if (isEmpty( )) return null;
  E answer = data[f];
  data[f] = null; // dereference to help garbage collection
  f = (f + 1) % data.length;
  sz--;
  return answer;
  }
  }

• LinkedQueue code:

• public class LinkedQueue<E> implements Queue<E> {
  private SinglyLinkedList<E> list = new SinglyLinkedList<>( ); // an empty list
  public LinkedQueue( ) { } // new queue relies on the initially empty list
  public int size( ) { return list.size( ); }
  public boolean isEmpty( ) { return list.isEmpty( ); }
  public void enqueue(E element) { list.addLast(element); }
  public E first( ) { return list.first( ); }
  public E dequeue( ) { return list.removeFirst( ); }
  }

• ArrayList Code:

• public class ArrayList<E> implements List<E> {
  // instance variables
  public static final int CAPACITY=16; // default array capacity
  private E[ ] data; // generic array used for storage
  private int size = 0; // current number of elements
  // constructors
  public ArrayList( ) { this(CAPACITY); } // constructs list with default capacity
  public ArrayList(int capacity) { // constructs list with given capacity
  data = (E[ ]) new Object[capacity]; // safe cast; compiler may give warning
  }
  // public methods
  /** Returns the number of elements in the array list. */
  public int size( ) { return size; }
  /** Returns whether the array list is empty. */
  public boolean isEmpty( ) { return size == 0; }
  /** Returns (but does not remove) the element at index i. */
  public E get(int i) throws IndexOutOfBoundsException {
  checkIndex(i, size);
  return data[i];
  }
  /** Replaces the element at index i with e, and returns the replaced element. */
  public E set(int i, E e) throws IndexOutOfBoundsException {
  checkIndex(i, size);
  E temp = data[i];
  data[i] = e;
  return temp;
  }
  /** Inserts element e to be at index i, shifting all subsequent elements later. */
  public void add(int i, E e) throws IndexOutOfBoundsException,
  IllegalStateException {
  checkIndex(i, size + 1);
  if (size == data.length) // not enough capacity
  throw new IllegalStateException("Array is full");
  for (int k=size-1; k>= i; k--) // start by shifting rightmost
  data[k+1] = data[k];
  data[i] = e; // ready to place the new element
  size++;
  }
  /** Removes/returns the element at index i, shifting subsequent elements earlier. */
  public E remove(int i) throws IndexOutOfBoundsException {
  checkIndex(i, size);
  E temp = data[i];
  for (int k=i; k< size-1; k++) // shift elements to fill hole
  data[k] = data[k+1];
  data[size-1] = null; // help garbage collection
  size--;
  return temp;
  }
  // utility method
  /** Checks whether the given index is in the range [0, n−1]. */
  protected void checkIndex(int i, int n) throws IndexOutOfBoundsException {
  if (i < 0 || i >= n)
  throw new IndexOutOfBoundsException("Illegal index: " + i);
  }
  
  /** Resizes internal array to have given capacity >= size. */
  protected void resize(int capacity) {
  E[ ] temp = (E[ ]) new Object[capacity]; // safe cast; compiler may give warning
  for (int k=0; k < size; k++)
  temp[k] = data[k];
  data = temp; // start using the new array
  }
  /** Inserts element e to be at index i, shifting all subsequent elements later. */

  }

Answer 1

To solve the given problem, the overall approach is to first add N integers to the concerned structure and then delete those N elements after the addition has been completed. To do this, run a for loop varying the value of N from 10 to 100,000,000 while checking for exception(outofmemoryerror) using try and catch block every time the structure is created of capacity N. When an exception is thrown, the loop breaks and goes to the next loop for the next structure. The time elapsed is calculated using System.nanoTime() which gives the current value of time and the elapsed time is calculated by tend - tstart.

In the end, a method is created which makes a 2d array corresponding to the value of N and time. There are 8 of these arrays. Two(add and delete) for each structure.

To create the ASCII table format(which is not shown in the question by the way), first, find out the maximum value of time and N and then convert them to string and store the corresponding length of the strings. Then run the for loop for the size of the array print the value of N and time with padding where the padding also includes the difference between the maximum string length and the current string length along with padding of size 2 on both the sides. In the below-given segment of code, I have only done this for the value of N but one can do this for the value of time also.

Remark: The code given below is giving an overall idea of what is to be done. It might not be accurate but is provided just for the sake of understanding. Also, the above given code in the question contains some error and needs to be corrected.

public class test
{

public static void main(String[] args) throws Exception
{
ArrayList<Float> asarray = new ArrayList<>();
ArrayList<Float> lsarray = new ArrayList<>();
ArrayList<Float> aqarray = new ArrayList<>();
ArrayList<Float> lqarray = new ArrayList<>();
ArrayList<Float> dasarray = new ArrayList<>();
ArrayList<Float> dlsarray = new ArrayList<>();
ArrayList<Float> daqarray = new ArrayList<>();
ArrayList<Float> dlqarray = new ArrayList<>();

int n = 0;
for(int i = 10; i<=100000000; i = i*10)
{
try
{

ArrayStack<Integer> as = new ArrayStack<>(i);
float tstart = (float)System.nanoTime();
for(int k = 0; k < i; k++)
{
as.push(1);

}
float tend = (float)System.nanoTime();
float time = 0;
if(i==10)
time = tend-tstart;
else
time = asarray.get(asarray.size()-1) + tend - tstart;
asarray.add(time);
n = i;

float dtstart = (float)System.nanoTime();
for(int k = 0; k < n; k++)
{
as.pop();

}
float dtend = (float)System.nanoTime();
float dtime =0;
if(i==10)
dtime = dtend-dtstart;
else
dtime = dasarray.get(dasarray.size()-1) + dtend - dtstart;
dasarray.add(dtime);
}
catch(OutOfMemoryError E)
{
break;
}

}

n = 0;
for(int i = 10; i<=100000000; i = i*10)
{
try
{

LinkedStack<Integer> ls = new LinkedStack<>(i);
float tstart = (float)System.nanoTime();
for(int k = 0; k < i; k++)
{
ls.push(1);

}
float tend =(float)System.nanoTime();
float time =0;
if(i==10)
time = tend-tstart;
else
time = lsarray.get(lsarray.size()-1) + tend - tstart;
lsarray.add(time);
n = i;

float dtstart = (float)System.nanoTime();
for(int k = 0; k < n; k++)
{
ls.pop();

}
float dtend = (float)System.nanoTime();
float dtime =0;
if(i==10)
dtime = dtend-dtstart;
else
dtime = dlsarray.get(dlsarray.size()-1) + dtend - dtstart;
dlsarray.add(dtime);
}
catch(OutOfMemoryError E)
{
break;
}

}

n = 0;
for(int i = 10; i<=100000000; i = i*10)
{
try
{

ArrayQueue<Integer> aq = new ArrayQueue<>(i);
float tstart = (float)System.nanoTime();
for(int k = 0; k < i; k++)
{
aq.enqueue(1);

}
float tend =(float)System.nanoTime();
float time =0;
if(i==10)
time = tend-tstart;
else
time = aqarray.get(aqarray.size()-1) + tend - tstart;
aqarray.add(time);
n = i;

float dtstart =(float)System.nanoTime();
for(int k = 0; k < n; k++)
{
aq.dequeue();

}
float dtend = (float)System.nanoTime();
float dtime =0;
if(i==10)
dtime = dtend-dtstart;
else
dtime = daqarray.get(daqarray.size()-1) + dtend - dtstart;
daqarray.add(dtime);
}
catch(OutOfMemoryError E)
{
break;
}

}

n = 0;
for(int i = 10; i<=100000000; i = i*10)
{
try
{

LinkedQueue<Integer> lq = new LinkedQueue<>(i);
float tstart = (float)System.nanoTime();
for(int k = 0; k < i; k++)
{
lq.enqueue(1);

}
float tend =(float)System.nanoTime();
float time =0;
if(i==10)
time = tend-tstart;
else
time = lqarray.get(lqarray.size()-1) + tend - tstart;
lqarray.add(time);
n = i;

float dtstart =(float)System.nanoTime();
for(int k = 0; k < n; k++)
{
lq.dequeue();

}
float dtend = (float)System.nanoTime();
float dtime =0;
if(i==10)
dtime = dtend-dtstart;
else
dtime = dlqarray.get(dlqarray.size()-1) + dtend - dtstart;
dlqarray.add(dtime);
}
catch(OutOfMemoryError E)
{
break;
}

}

float[][] as = to2d(asarray);
float[][] das = to2d(dasarray);
float[][] ls = to2d(lsarray);
float[][] dls = to2d(dlsarray);
float[][] aq = to2d(aqarray);
float[][] daq = to2d(daqarray);
float[][] lq = to2d(lqarray);
float[][] dlq = to2d(dlqarray);

totable(asarray);
totable(dasarray);
totable(lsarray);
totable(dlsarray);
totable(aqarray);
totable(daqarray);
totable(lqarray);
totable(dlqarray);

}
public float[][] to2d(ArrayList<Float> asarray)
{
float[][] asarr = new float[asarray.size()][2];
float m=10;
for(int i=0;i<asarray.size();i++)
{
asarr[i][0]=m;
m=m*10;
asarr[i][1]=asarray.get(i);
}
return asarr;
}

public void totable(float[][] arr)
{

int maxlen = 9
System.out.print("| N |"+"| time ");

for(int i=0;i<arr.length(0);i++)
{

int curlen = (String.valueOf(arr[i][0])).length();
String space = "";
for(int k = 0; k < maxlen - curlen; k++)
{
space += " "
}
System.out.print("| " + arr[i][0] + space + " |");
System.out.print("| " + arr[i][1] + " |");

System.out.println();
}
}

}

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