package algs43;
import stdlib.*;
/* ***********************************************************************
* Compilation: javac Edge.java
* Execution: java Edge
*
* Immutable weighted edge.
*
*************************************************************************/
/**
* The {@code Edge} class represents a weighted edge in an undirected graph.
*
* For additional documentation, see Section 4.3 of
* Algorithms, 4th Edition by Robert Sedgewick and Kevin Wayne.
*/
public class Edge implements Comparable {
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 Error("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 %.2f", v, w, weight);
}
/**
* Test client.
*/
public static void main(String[] args) {
Edge e = new Edge(12, 23, 3.14);
StdOut.println(e);
}
}