Find indegree and outdegree of a directed graph in scala

Scala program for Find indegree and outdegree of a directed graph. Here problem description and other solutions.

/*
    Scala Program for 
    Show degree of vertex in directed graph
*/
class AjlistNode(
	// Vertices node key
	var id: Int,
		var next: AjlistNode)
{
	def this(id: Int)
	{
		// Set value of node key
		this(id, null);
	}
}
class Vertices(var data: Int,
	var next: AjlistNode,
		var last: AjlistNode)
{
	def this(data: Int)
	{
		this(data, null, null);
	}
}
class Graph(
	// Number of Vertices
	var size: Int,
		var node: Array[Vertices])
{
	def this(size: Int)
	{
		this(size, Array.fill[Vertices](size)(null));
      	// Set value
		this.setData();
	}
	// Set initial node value
	def setData(): Unit = {
		if (size <= 0)
		{
			println("\nEmpty Graph");
		}
		else
		{
			var index: Int = 0;
			while (index < size)
			{
				// Set initial node value
				node(index) = new Vertices(index);
				index += 1;
			}
		}
	}
	//  Handling the request of adding new edge
	def addEdge(start: Int, last: Int): Unit = {
		if (start >= 0 && start < size && 
             last >= 0 && last < size)
		{
			// Safe connection
			var edge: AjlistNode = new AjlistNode(last);
			if (node(start).next == null)
			{
				node(start).next = edge;
			}
			else
			{
				// Add edge at the end
				node(start).last.next = edge;
			}
			// Get last edge 
			node(start).last = edge;
		}
		else
		{
			// When invalid nodes
			println("\nHere Something Wrong");
		}
	}
	def printGraph(): Unit = {
		if (size > 0)
		{
			var index: Int = 0;
			// Print graph ajlist Node value
			while (index < size)
			{
				print("\nAdjacency list of vertex " + index + " : ");
				var temp: AjlistNode = node(index).next;
				while (temp != null)
				{
					// Display graph node 
					print(" " + node(temp.id).data);
					// Visit to next edge
					temp = temp.next;
				}
				index += 1;
			}
		}
	}
	// Find indegree and outdegree of 
	// each nodes of a given graph
	def findDegree(indegree: Array[Int], 
      outdegree: Array[Int]): Unit = {
		var temp: AjlistNode = null;
		var length: Int = 0;
		var i: Int = 0;
		while (i < this.size)
		{
			temp = this.node(i).next;
			length = 0;
			while (temp != null)
			{
				// Update indegree
				indegree(temp.id) += 1;
				temp = temp.next;
				length += 1;
			}
			// Set outdegree value
			outdegree(i) = length;
			i += 1;
		}
	}
	def showDegree(): Unit = {
		if (this.node != null)
		{
			var indegree: Array[Int] = Array.fill[Int](this.size)(0);
			var outdegree: Array[Int] = Array.fill[Int](this.size)(0);
			// Find degree
			this.findDegree(indegree, outdegree);
			println("\n");
			var i: Int = 0;
			// Display result
			while (i < this.size)
			{
				println("Node [" + i + 
                        "] indegree [" + 
                        indegree(i) + "] outdegree [" + 
                        outdegree(i) + "]");
				i += 1;
			}
		}
		else
		{
			print("Empty Graph");
		}
	}
}
object Main
{
	def main(args: Array[String]): Unit = {
		// 6 implies the number of nodes in graph
		var g: Graph = new Graph(6);
		// Connected two node with Edges
		g.addEdge(0, 1);
		g.addEdge(0, 2);
		g.addEdge(0, 5);
		g.addEdge(2, 3);
		g.addEdge(3, 1);
		g.addEdge(4, 0);
		g.addEdge(4, 1);
		g.addEdge(5, 0);
		g.addEdge(5, 2);
		g.printGraph();
		// Test
		g.showDegree();
	}
}

Output

Adjacency list of vertex 0 :  1 2 5
Adjacency list of vertex 1 :
Adjacency list of vertex 2 :  3
Adjacency list of vertex 3 :  1
Adjacency list of vertex 4 :  0 1
Adjacency list of vertex 5 :  0 2

Node [0] indegree [2] outdegree [3]
Node [1] indegree [3] outdegree [0]
Node [2] indegree [2] outdegree [1]
Node [3] indegree [1] outdegree [1]
Node [4] indegree [0] outdegree [2]
Node [5] indegree [1] outdegree [2]