content: /*************************************************************************
   *  Compilation:  javac Edge.java
   *  Execution:    java Edge
   *
   *  Immutable weighted edge.
   *
   *************************************************************************/
  
  /**
   *  The <tt>Edge</tt> class represents a weighted edge in an undirected graph.
   *  <p>
   *  For additional documentation, see <a href="http://algs4.cs.princeton.edu/43mst">Section 4.3</a> of
   *  <i>Algorithms, 4th Edition</i> by Robert Sedgewick and Kevin Wayne.
   */
  public class Edge implements Comparable<Edge> { 
  
      private final int v;
      private final int w;
      private final double weight;
  
     /**
       * Create an edge between v and w with given weight.
       */
      public Edge(int v, int w, double weight) {
          this.v = v;
          this.w = w;
          this.weight = weight;
      }
  
     /**
       * Return the weight of this edge.
       */
      public double weight() {
          return weight;
      }
  
     /**
       * Return either endpoint of this edge.
       */
      public int either() {
          return v;
      }
  
     /**
       * Return the endpoint of this edge that is different from the given vertex
       * (unless a self-loop).
       */
      public int other(int vertex) {
          if      (vertex == v) return w;
          else if (vertex == w) return v;
          else throw new RuntimeException("Illegal endpoint");
      }
  
     /**
       * Compare edges by weight.
       */
      public int compareTo(Edge that) {
          if      (this.weight() < that.weight()) return -1;
          else if (this.weight() > that.weight()) return +1;
          else                                    return  0;
      }
  
  
     /**
       * Return a string representation of this edge.
       */
      public String toString() {
          return String.format("%d-%d %.5f", v, w, weight);
      }
  
  
     /**
       * Test client.
       */
      public static void main(String[] args) {
          Edge e = new Edge(12, 23, 3.14);
          StdOut.println(e);
      }
  }
  