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package algs44;
import stdlib.*;
/* ***********************************************************************
 *  Compilation:  javac DirectedEdge.java
 *  Execution:    java DirectedEdge
 *
 *  Immutable weighted directed edge.
 *
 *************************************************************************/

/**
 *  The <tt>DirectedEdge</tt> class represents a weighted edge in an directed graph.
 *  <p>
 *  For additional documentation, see <a href="http://algs4.cs.princeton.edu/44sp">Section 4.4</a> of
 *  <i>Algorithms, 4th Edition</i> by Robert Sedgewick and Kevin Wayne.
 */

public class DirectedEdge implements Comparable<DirectedEdge> {
  private final int v;
  private final int w;
  private final double weight;

  /**
   * Create a directed edge from v to w with given weight.
   */
  public DirectedEdge(int v, int w, double weight) {
    this.v = v;
    this.w = w;
    this.weight = weight;
  }

  /**
   * Return the vertex where this edge begins.
   */
  public int from() {
    return v;
  }

  /**
   * Return the vertex where this edge ends.
   */
  public int to() {
    return w;
  }

  /**
   * Return the weight of this edge.
   */
  public double weight() { return weight; }

  /**
   * Return a string representation of this edge.
   */
  public String toString() {
    return String.format("%d->%d %.2f", v, w, weight);
  }

  /**
   * Compare by weights.
   */
  public int compareTo (DirectedEdge o) {
    if (weight < o.weight) return -1;
    if (weight > o.weight) return 1;
    return 0;
  }

  /**
   * Test client.
   */
  public static void main(String[] args) {
    DirectedEdge e = new DirectedEdge(12, 23, 3.14);
    StdOut.println(e);
  }
}