Generating user defined Graph nodes

Question

Can anyone tell me how I can generate a user defined number of Graph.Nodes from the keyboard instead of going through them one at a time please. I have tried to use a for loop but I can't get it to work.
Can anyone help.
import java.util.Iterator;
public class GraphTest{
     public static void main(String[] args){
          ASDigraph graph = new ASDigraph();
                                           // Instead of the following I would like the user to type a number
          // from the keyboard to generate any number of nodes.
          Graph.Node nodeA = graph.addNode("A");
          Graph.Node nodeB = graph.addNode("B");
          Graph.Node nodeC = graph.addNode("C");
          Graph.Node nodeD = graph.addNode("D");
          Graph.Node nodeE = graph.addNode("E");
          Graph.Node nodeF = graph.addNode("F");
          // There is other code here to generate random edges to each
          // vertex
          Iterator iter;
          iter = graph.successors(nodeA);
          System.out.println("Depth first search starting at A:");
          while(iter.hasNext()){
               Graph.Node node = (Graph.Node) iter.next();
               System.out.print(node.getElement() + " ");
          System.out.println('\n');
}This is the method used to add a node to the graph. This is taken from the ASDigraph class
public Graph.Node addNode (Object elem) {
    // Add to this graph a new node containing element elem, but with no
    // connecting edges, and return the new node.
        ASDigraph.Node node = new ASDigraph.Node(elem);
        node.prevNode = null;
        node.nextNode = firstNode;
        firstNode = node;
        size++;
        return node;
    }I also use this Input class for user entry from the keyboard. For instance: -
// Create nodes
          System.out.print("Enter the number of nodes : ");
          nodeLength = new int[Input.readInt()];
          //Initialize each node an element
          for(i=1; i<nodeLength.length; i++){     
                                                 // I tried to put code here to generate graph nodes          
// class starts here
import java.io.*;
public class Input
        public static int readInt()
           byte nos[] = new byte[12];  //*** Stores characters read ***
           int noread;                 //*** Number of characters read ***
           //*** Read keys pressed as a set of bytes ***
           try
                noread = System.in.read(nos) - 2; //*** Ignore \n and \r ***
           catch(IOException e){}
           int v = 0;
           int multiplier = 1;
           int start = 0;
           //*** IF it starts with a minus THEN ***
           if(nos[0]=='-')
                //*** Start at the second char and change the sign ***
                start=1;
                multiplier= -1;
           //*** Create a value from the bytes ***
           for(int c=start;nos[c] !=13;c++)
                v = v*10 + nos[c] - '0';
           return v*multiplier;
        public static float readFloat()
           byte nos[] = new byte[15];
           int noread;
           //*** Read keys pressed as a set of bytes ***
           try
                noread = System.in.read(nos) - 2; //*** Ignore \n and \r
           catch(IOException e){}
           boolean frac=false;
           float v=0;
           float dp=0;
           int multiplier=1;
           int start=0;
           //*** IF first character is minus THEN ***
           if(nos[0]=='-')
                //***Start at second character and change sign ***
                start=1;
                multiplier=1;
           //*** Convert to number ***
           for(int c=start; nos[c]!=13; c++)
                if(nos[c]==(int)'.')
                        frac=true;
                        dp=10;
                        continue;
                 if(!frac)
                        v = v*10 +nos[c] - '0';
                 else
                        v = v+(float)((nos[c]-'0')/dp);
                        dp*=10;
            return v*multiplier;
         public static char readChar()
           byte nos[] = new byte[10];
           int noread=0;
           //*** Read keys pressed as a set of bytes ***
           try
                noread = System.in.read(nos) - 2; //*** Ignore \n and \r
           catch(IOException e){}
           if(noread>0)
                return (char)nos[0];
           else
                return'\0';
         public static String readString()
           byte nos[] = new byte[80];
           int noread=0;
           //*** Read keys pressed as a set of bytes ***
           try
                noread = System.in.read(nos) - 2; //*** Ignore \n and \r
           catch(IOException e){}
           String s="";
           //*** Convert bytes to  characters and add to string ***
           for(int p=0; p<noread; p++)
                s=s+(char)nos[p];
           return s;

Answer 1

ASDigraph graph = new ASDigraph();
// Create nodes
System.out.print("Enter the number of nodes : ");
int nodeLength = Input.readInt();
//Initialize each node an element
char currentCar = 'A';
for (int i = 0; i < nodeLength; i++) {     
    graph.addNode(String.valueOf(currentCar));
    currentCar++;