Dynamic creation of objects at runtime

Question

supposed i want to create a tree structure and i use objects to represent the nodes...but i need the user to specify the number of nodes in the tree...so the user will enter 10 or 13 whatever.So how do we create those nodes dynamically...i know how to add nodes ...umm Example
Node A=new node('A');
Node B=new node('B');
//this creates a new node A of type node(user defined class)
but how to create it dynamicaaly
eg
for(i=1;i<=Totalnodes;i++)
Node A= new node('A');
} //well obviously this code is wrong .
Here is a copy of the main program where nodes are added to the code and not specified by the user
public class Main {
     public static void main(String[] args)
          //Lets create nodes as given as an example in the article
          Node nA=new Node('A');
          Node nB=new Node('B');
          Node nC=new Node('C');
          Node nD=new Node('D');
          Node nE=new Node('E');
          Node nF=new Node('F');
          //Create the graph, add nodes, create edges between nodes
          Graph g=new Graph();
          g.addNode(nA);
          g.addNode(nB);
          g.addNode(nC);
          g.addNode(nD);
          g.addNode(nE);
          g.addNode(nF);
          g.setRootNode(nA);
          g.connectNode(nA,nB);
          g.connectNode(nA,nC);
          g.connectNode(nA,nD);
          g.connectNode(nB,nE);
          g.connectNode(nB,nF);
          g.connectNode(nC,nF);
.

Answer 1

Ugh i so messed up..ok ok im gonna explain clearly now coz i just kinda blurted out stuff before :P
ok So here is the main program :
public class Main {
     public static void main(String[] args)
          //Lets create nodes as given as an example in the article
          Node nA=new Node('A');
          Node nB=new Node('B');
          Node nC=new Node('C');
          Node nD=new Node('D');
          Node nE=new Node('E');
          Node nF=new Node('F');
          //Create the graph, add nodes, create edges between nodes
          Graph g=new Graph();
          g.addNode(nA);
          g.addNode(nB);
          g.addNode(nC);
          g.addNode(nD);
          g.addNode(nE);
          g.addNode(nF);
          g.setRootNode(nA);
          g.connectNode(nA,nB);
          g.connectNode(nA,nC);
          g.connectNode(nA,nD);
          g.connectNode(nB,nE);
          g.connectNode(nB,nF);
          g.connectNode(nC,nF);
          //Perform the traversal of the graph
          System.out.println("DFS Traversal of a tree is ------------->");
          g.dfs();
          System.out.println("\nBFS Traversal of a tree is ------------->");
          g.bfs();
And this is the Graph module:
import java.util.ArrayList;
import java.util.LinkedList;
import java.util.Queue;
import java.util.Stack;
public class Graph
     public Node rootNode;
     public ArrayList nodes=new ArrayList();
     public int[][] adjMatrix;//Edges will be represented as adjacency Matrix
     int size;
     public void setRootNode(Node n)
          this.rootNode=n;
     public Node getRootNode()
          return this.rootNode;
     public void addNode(Node n)
          nodes.add(n);
     //This method will be called to make connect two nodes
     public void connectNode(Node start,Node end)
          if(adjMatrix==null)
               size=nodes.size();
               adjMatrix=new int[size][size];
          int startIndex=nodes.indexOf(start);
          int endIndex=nodes.indexOf(end);
          adjMatrix[startIndex][endIndex]=1;
          adjMatrix[endIndex][startIndex]=1;
     private Node getUnvisitedChildNode(Node n)
          int index=nodes.indexOf(n);
          int j=0;
          while(j<size)
               if(adjMatrix[index][j]==1 && ((Node)nodes.get(j)).visited==false)
                    return (Node)nodes.get(j);
               j++;
          return null;
     //BFS traversal of a tree is performed by the bfs() function
     public void bfs()
          //BFS uses Queue data structure
          Queue q=new LinkedList();
          q.add(this.rootNode);
          printNode(this.rootNode);
          rootNode.visited=true;
          while(!q.isEmpty())
               Node n=(Node)q.remove();
               Node child=null;
               while((child=getUnvisitedChildNode(n))!=null)
                    child.visited=true;
                    printNode(child);
                    q.add(child);
          //Clear visited property of nodes
          clearNodes();
     //DFS traversal of a tree is performed by the dfs() function
     public void dfs()
          //DFS uses Stack data structure
          Stack s=new Stack();
          s.push(this.rootNode);
          rootNode.visited=true;
          printNode(rootNode);
          while(!s.isEmpty())
               Node n=(Node)s.peek();
               Node child=getUnvisitedChildNode(n);
               if(child!=null)
                    child.visited=true;
                    printNode(child);
                    s.push(child);
               else
                    s.pop();
          //Clear visited property of nodes
          clearNodes();
     //Utility methods for clearing visited property of node
     private void clearNodes()
          int i=0;
          while(i<size)
               Node n=(Node)nodes.get(i);
               n.visited=false;
               i++;
     //Utility methods for printing the node's label
     private void printNode(Node n)
          System.out.print(n.label+" ");
And this is the node module:
public class Node
     public char label;
     public boolean visited=false;
     public Node(char l)
          this.label=l;
So my question is: How do i get the user to specify the number of nodes..i.e take input the number of nodes...add them to a tree....and how do i convert this graph into a tree