Inital commitHEADmaster

4 files changed, 178 insertions, 0 deletions

diff --git a/labs/lab09_iterator/Iterator.java b/labs/lab09_iterator/Iterator.java
new file mode 100644
index 0000000..4d64f9e
--- /dev/null
+++ b/labs/lab09_iterator/Iterator.java
@@ -0,0 +1,7 @@
+
+public interface Iterator<T>
+{
+	public boolean hasNext();
+	public T next();
+	public T remove();
+}
diff --git a/labs/lab09_iterator/SListIterator.java b/labs/lab09_iterator/SListIterator.java
new file mode 100644
index 0000000..e58ea6d
--- /dev/null
+++ b/labs/lab09_iterator/SListIterator.java
@@ -0,0 +1,88 @@
+import java.util.NoSuchElementException;
+
+
+public class SListIterator<T>
+{
+	private Node firstNode;
+	private int numberOfEntries;
+	
+	public SListIterator()
+	{
+		firstNode = null;
+		numberOfEntries = 0;
+	}
+	
+	public void addToFirst(T aData)
+	{
+		firstNode = new Node(aData, firstNode);
+		numberOfEntries++;
+	}
+	
+	public T getEntry(int givenPosition)
+	{
+		T result = null;
+		
+		if((givenPosition >= 1) && (givenPosition <= numberOfEntries))
+		{
+			result = (getNodeAt(givenPosition)).data;
+		}
+		
+		return result;
+	}
+	
+	private Node getNodeAt(int givenPosition)
+	{
+		Node currentNode = firstNode;
+		
+		for(int counter = 1; counter < givenPosition; counter++)
+		{
+			currentNode = currentNode.next;
+		}
+		
+		return currentNode;
+	}
+	
+	public Iterator<T> getIterator()
+	{
+		return new IteratorForSList();
+	}
+	
+	private class IteratorForSList implements Iterator<T>
+	{
+		Node node;
+		
+		private IteratorForSList()
+		{
+			node = firstNode;
+		}
+		
+		public boolean hasNext()
+		{
+			return node != null;
+		}
+		
+		public T next()
+		{
+			T temp = node.data;
+			node = node.next;
+			return temp;
+		}
+		
+		public T remove()
+		{
+			throw new UnsupportedOperationException("remove() is not supported by this iterator");
+		}
+	}
+	
+	private class Node
+	{
+		private T data;
+		private Node next;
+		
+		private Node(T aData, Node nextNode)
+		{
+			data = aData;
+			next = nextNode;
+		}
+	}
+}
diff --git a/labs/lab09_iterator/SListIteratorTester.java b/labs/lab09_iterator/SListIteratorTester.java
new file mode 100644
index 0000000..b6960b5
--- /dev/null
+++ b/labs/lab09_iterator/SListIteratorTester.java
@@ -0,0 +1,83 @@
+import java.util.Random;
+
+public class SListIteratorTester
+{
+	public static void main(String[] args)
+	{
+		// Construct a list and add entries
+		
+		int numberOfData = 50000;	// number of data to add to the list
+		int maxDataValue = 10;	// number of different values to add to the list
+		int[] getEntryArray = new int[numberOfData];
+		int[] iteratorArray = new int[numberOfData];
+		
+		SListIterator<Integer> list = new SListIterator<Integer>();
+		
+		Random rand = new Random();
+		rand.setSeed(System.nanoTime());
+		
+		System.out.print("Adding data into the list: ");
+		
+		for(int i = 0; i < numberOfData; i++)
+		{
+			list.addToFirst(rand.nextInt(maxDataValue));
+		}
+		
+		System.out.println("Done");
+
+		System.out.print("Dry run for the method getEntry(): ");
+		for(int i = 1; i <= 10; i++)
+		{
+			list.getEntry(i);
+		}
+		System.out.println("Done");
+		
+		
+		double startTime;	// Start time millisecond
+		double endTime;		// End time millisecond
+
+		System.out.print("Time the method getEntry(): ");
+		
+		// Timing the method getEntry()
+		
+		startTime = System.currentTimeMillis();		
+		
+		for(int i = 1; i <= numberOfData; i++)
+		{
+			getEntryArray[i - 1] = list.getEntry(i);
+		}
+		
+		endTime = System.currentTimeMillis();
+		System.out.println("Done");
+		double getEntryTime = endTime - startTime;
+		
+		System.out.print("Time the iterator: ");
+
+		Iterator<Integer> iterator = list.getIterator();
+		
+		startTime = System.currentTimeMillis();
+		
+		int index = 0;
+		
+		while(iterator.hasNext())
+		{
+			iteratorArray[index] = iterator.next();
+			index++;
+		}
+		
+		endTime = System.currentTimeMillis();
+		System.out.println("Done");
+		double iteratorTime = endTime - startTime;
+
+		for(int i = 0; i < numberOfData; i++)
+		{
+			if(getEntryArray[i] != iteratorArray[i])
+			{
+				System.out.println("There is something wrong with your iterator.");
+			}
+		}
+		
+		System.out.println("The method getEntry() took " + getEntryTime + " milliseconds.");
+		System.out.println("Using iterator took " + iteratorTime + " milliseconds.");
+	}
+}
\ No newline at end of file
diff --git a/labs/lab09_iterator/lab09_iterator.pdf b/labs/lab09_iterator/lab09_iterator.pdf
new file mode 100644
index 0000000..c9a43f1
--- /dev/null
+++ b/labs/lab09_iterator/lab09_iterator.pdf