13.21 CODE LISTINGS

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/*
 Graph class implemented with adjacency matrix: 1-D array for vertices, 2-D array to store edge information.
 Displays contents of both tables
   traversal depth-first with a Stack

					  

   breadth-first using a Queue
  searches for a path by depth-first algorithm, together with distance
 Graph is directed & uses the 7 town names below

Introducing Data Structures with Java
David Cousins 2010
*/
public class Graph {
  static String[] Vertex = new String[7];
  static boolean[] visited = new boolean[7];
  static int[][] Edge = new int[7][7];
  static DLNode head = new DLNode(0);
  static DLNode end = new DLNode(0);
  Graph() {
    // set Vertex identifiers

    Vertex[0] = "Sleepytown";
    Vertex[1] = "Much Snoring";
    Vertex[2] = "Great Snoring";
    Vertex[3] = "Little Snoring";
    Vertex[4] = "Lesser Snoring";
    Vertex[5] = "Snoring on Sea";
    Vertex[6] = "Snoring on the Hill";

    for (int i = 0; i < 7; i++)
       visited[i] = false;

    // initialise edges to blank
    for (int i = 0; i < 7; i++)
       for (int j = 0; j < 7; j++)
          Edge[i][j] = 0;

    // set edge value weightings in the table
    Edge[0][1] = 50;  // Sleepytown to Much Snoring
    Edge[1][0] = 50;  // Much Snoring to Sleepytown
    Edge[1][2] = 150; // Much Snoring to Great Snoring
    Edge[2][1] = 150; // Great Snoring to Much Snoring
    Edge[3][1] = 80;  // Little Snoring to Much Snoring
    Edge[2][3] = 180; // Great Snoring to Little Snoring
    Edge[2][6] = 150; // Great Snoring to Snoring on the Hill
    Edge[2][5] = 200; // Great Snoring to Snoring by Sea
    Edge[5][2] = 200; // Snoring on Sea to Great Snoring
    Edge[6][4] = 50;  // Snoring on the Hill to Lesser Snoring
    Edge[4][2] = 180; // Lesser Snoring to Great Snoring
 }
 // display format utility
 public void formatLine(String item){
   int spaces = 25 - item.length();
   for (int i = 0; i<spaces; i++)
      System.out.print(" ");;
 }
 // displays all graph data