singlelovlist.java

软件工程实践课程的答案哦

class SingleLOVList
{
	SingleLOV head;
	SingleLOV rear ;
	SingleLOVList()
	{
		head = null;
		rear = null;
	}
	/**make the list empty*/
	public void clear()
	{
		head = null;
		rear = null;
	}
	/** add a lov node to the list
	 * @param lov the node to add*/
	public void add(SingleLOV lov)
	{
		
		
		if(head == null)
		{
			head = lov;
			rear = head;
		}
		else
		{
			rear.next = lov;
			rear = rear.next;
		}
	
	}
	/**
	 * del a lov object from the list
	 * @param lov the node to del
	 */
	public void del(SingleLOV lov)
	{   
		SingleLOV ptr = head;
		SingleLOV ptr2 = head;
		
		if(ptr==null)//empty
		{
			System.out.println("NO SingleLOV in SingleLOVList!");
			return;
		}
		
		else
		{
			ptr2 = ptr;
			while(ptr!=null&&!ptr.equals(lov))
			{
				ptr2 = ptr;
				ptr = ptr.next;
			}
			if(ptr==head)//first node
				head = head.next;
			else if(ptr==rear)//last
			{
				ptr2.next= ptr2.next.next;
				rear = ptr2;
			}
			else if(ptr!=null)
			{   //System.out.println("ptr: "+ptr);
			//System.out.println("ptr2: "+ptr2);
				ptr2.next= ptr.next;
			}
		}
	
	}
	/**
	 * @return the length of the list*/
	public int getLength()
	{
		int i=0;
		for(SingleLOV ptr = head;ptr!=null;ptr = ptr.next)
		{
			i++;
		}
		return i;
	}
	public void print()
	{
		for(SingleLOV ptr = head;ptr!=null;ptr = ptr.next)
		{
			System.out.print(ptr.x+","+ptr.y+","+ptr.color);
			System.out.println();
		}
	}
	public static void main(String[] args)
	{
		SingleLOVList list = new SingleLOVList();
	
		list.add(new SingleLOV(1,1,2));
		list.add(new SingleLOV(2,1,2));
		list.add(new SingleLOV(3,1,2));
	
		//	list.add(new SingleLOV(34,2,3));
		list.print();
		System.out.println(list.getLength());
			list.del(new SingleLOV(1,1,2));
			list.del(new SingleLOV(3,1,2));
			
		list.print();
	System.out.println(list.getLength());
			list.add(new SingleLOV(1,1,2));
			list.add(new SingleLOV(3,1,2));
		list.print();
	System.out.println(list.getLength());
	}
}