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Thread: Graph class, ToString help.

  1. #1
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    Default Graph class, ToString help.

    Hello,

    I have an assignment that I'm working on, I have completed every thing but one part, the toString of the Graph Class. I am having a hard time creating my toString.

    The professor wants us to use both the vertexIterator and the outEdges methods in the Graph class to represent our toString. Here is the code I wrote in the Graph class.

        import java.util.*;
        public class Graph
       {
          private List<Edge> outEdge;
          private List<Vertex> verticies; 
          private List<Edge> edges;
          private int numberEdges;
          private int numberVertices;
     
     
           public Graph() 
          {
             numberVertices = 0;
             numberEdges = 0;
             verticies = new ArrayList<Vertex>();
             edges = new ArrayList<Edge>();
     
          }
           public void addVertex(Vertex v) 
          {
             numberVertices++;
             verticies.add(v);
             outEdge = v.getAdjacentList();
          }
           public void addEdge(Edge e) 
          {
             numberEdges++;
             edges.add(e);
             outEdge.add(e);
     
          }
     
           public int numVertices() 
          {
             return numberVertices;
          }
     
           public int numEdges()
          {
             return numberEdges;
          }
     
           public Iterator outEdges(Vertex v)
          {
             //outEdge = v.getAdjacentList();       
             return v.outEdges();
          }
     
           public Iterator vertexIterator()
          {
             return verticies.iterator();
          }
     
           public String toString()
          {
             StringBuffer tmp = new StringBuffer();
     
     
             for(Iterator vIterator = vertexIterator(); vIterator.hasNext(); )
                Vertex v = (Vertex) vIterator.next();   	   
             tmp.append("outgoing edges from vertex: ");
             for (Iterator it = v.outEdges(v); it.hasNext(); ) 
             {
                Edge s = (Edge)it.next(); 
                tmp.append(s);
             } 
             return tmp.toString();
          }
     
       }

    This is the error message I'm getting

    Graph.java:68: not a statement
    Vertex v = (Vertex) vIterator.next();
    ^
    Graph.java:68: ';' expected
    Vertex v = (Vertex) vIterator.next();
    ^
    2 errors
    This is literally the final part of my project. I don't know how to get the Vertex section correct. Any help will be greatly appreciated.

    If you need the rest of my code, I can provide it.


  2. #2
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    Default Re: Graph class, ToString help.

    Hello johnjames!
    The {} are missing after the for loop.

  3. The Following User Says Thank You to andreas90 For This Useful Post:

    johnjames (April 28th, 2012)

  4. #3
    Administrator copeg's Avatar
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    Default Re: Graph class, ToString help.

    Take note of the scope of the variables, and the usage (or lackthereof) of brackets in your for loop.

  5. The Following User Says Thank You to copeg For This Useful Post:

    johnjames (April 28th, 2012)

  6. #4
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    Default Re: Graph class, ToString help.

    Thank You for your responses andreas90 and copeg! So simple. Now I gotta rework my toString code so it can print the proper output.

    If I have anymore questions about this toString, I will definitely ask in here.

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