In my code I am trying to derive an adjacency matrix, but I'm getting the following exception.
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 3
at AdjMatrixDigraph.main(AdjMatrixDigraph.java:90)
AdjMatrixDigraph.java
import java.util.Iterator;
import java.util.NoSuchElementException;
public class AdjMatrixDigraph extends StdOut {
private int V;
private int E;
private boolean[][] adj;
// empty graph with V vertices
public AdjMatrixDigraph(int V) {
if (V < 0) throw new RuntimeException("Number of vertices must be nonnegative");
this.V = V;
this.E = 0;
this.adj = new boolean[V][V];
}
// random graph with V vertices and E edges
public AdjMatrixDigraph(int V, int E) {
this(V);
if (E < 0) throw new RuntimeException("Number of edges must be nonnegative");
if (E > V*V) throw new RuntimeException("Too many edges");
// can be inefficient
while (this.E != E) {
int v = (int) (V * Math.random());
int w = (int) (V * Math.random());
addEdge(v, w);
}
}
// number of vertices and edges
public int V() { return V; }
public int E() { return E; }
// add directed edge v->w
public void addEdge(int v, int w) {
if (!adj[v][w]) E++;
adj[v][w] = true;
}
// return list of neighbors of v
public Iterable<Integer> adj(int v) {
return new AdjIterator(v);
}
// support iteration over graph vertices
private class AdjIterator implements Iterator<Integer>, Iterable<Integer> {
private int v, w = 0;
AdjIterator(int v) { this.v = v; }
public Iterator<Integer> iterator() { return this; }
public boolean hasNext() {
while (w < V) {
if (adj[v][w]) return true;
w++;
}
return false;
}
public Integer next() {
if (hasNext()) { return w++; }
else { throw new NoSuchElementException(); }
}
public void remove() { throw new UnsupportedOperationException(); }
}
// string representation of Graph - takes quadratic time
public String toString() {
String NEWLINE = System.getProperty("line.separator");
StringBuilder s = new StringBuilder();
s.append(V + " " + E + NEWLINE);
for (int v = 0; v < V; v++) {
s.append(v + ": ");
for (int w : adj(v)) {
s.append(w + " ");
}
s.append(NEWLINE);
}
return s.toString();
}
// test client
public static void main(String[] args) {
int V = Integer.parseInt(args[3]);
int E = Integer.parseInt(args[1]);
AdjMatrixDigraph G = new AdjMatrixDigraph(V, E);
StdOut.println(G);
}
}
StdOut.java
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.io.UnsupportedEncodingException;
import java.util.Locale;
/**
* <i>Standard output</i>. This class provides methods for writing strings
* and numbers to standard output.
* <p>
* For additional documentation, see <a href="http://introcs.cs.princeton.edu/15inout">Section 1.5</a> of
* <i>Introduction to Programming in Java: An Interdisciplinary Approach</i> by Robert Sedgewick and Kevin Wayne.
*/
public class StdOut {
// force Unicode UTF-8 encoding; otherwise it's system dependent
public static final String charsetName = "UTF-8";
// assume language = English, country = US for consistency with StdIn
private static final Locale US_LOCALE = new Locale("en", "US");
// send output here
private static PrintWriter out;
// this is called before invoking any methods
static {
try {
out = new PrintWriter(new OutputStreamWriter(System.out, charsetName), true);
}
catch (UnsupportedEncodingException e) { System.out.println(e); }
}
// don't instantiate
public StdOut() {
}
// close the output stream (not required)
/**
* Close standard output.
*/
public static void close() {
out.close();
}
/**
* Terminate the current line by printing the line separator string.
*/
public static void println() {
out.println();
}
/**
* Print an object to standard output and then terminate the line.
*/
public static void println(Object x) {
out.println(x);
}
/**
* Print a boolean to standard output and then terminate the line.
*/
public static void println(boolean x) {
out.println(x);
}
/**
* Print a char to standard output and then terminate the line.
*/
public static void println(char x) {
out.println(x);
}
/**
* Print a double to standard output and then terminate the line.
*/
public static void println(double x) {
out.println(x);
}
/**
* Print a float to standard output and then terminate the line.
*/
public static void println(float x) {
out.println(x);
}
/**
* Print an int to standard output and then terminate the line.
*/
public static void println(int x) {
out.println(x);
}
/**
* Print a long to standard output and then terminate the line.
*/
public static void println(long x) {
out.println(x);
}
/**
* Print a short to standard output and then terminate the line.
*/
public static void println(short x) {
out.println(x);
}
/**
* Print a byte to standard output and then terminate the line.
*/
public static void println(byte x) {
out.println(x);
}
/**
* Flush standard output.
*/
public static void print() {
out.flush();
}
/**
* Print an Object to standard output and flush standard output.
*/
public static void print(Object x) {
out.print(x);
out.flush();
}
/**
* Print a boolean to standard output and flush standard output.
*/
public static void print(boolean x) {
out.print(x);
out.flush();
}
/**
* Print a char to standard output and flush standard output.
*/
public static void print(char x) {
out.print(x);
out.flush();
}
/**
* Print a double to standard output and flush standard output.
*/
public static void print(double x) {
out.print(x);
out.flush();
}
/**
* Print a float to standard output and flush standard output.
*/
public static void print(float x) {
out.print(x);
out.flush();
}
/**
* Print an int to standard output and flush standard output.
*/
public static void print(int x) {
out.print(x);
out.flush();
}
/**
* Print a long to standard output and flush standard output.
*/
public static void print(long x) {
out.print(x);
out.flush();
}
/**
* Print a short to standard output and flush standard output.
*/
public static void print(short x) {
out.print(x);
out.flush();
}
/**
* Print a byte to standard output and flush standard output.
*/
public static void print(byte x) {
out.print(x);
out.flush();
}
/**
* Print a formatted string to standard output using the specified
* format string and arguments, and flush standard output.
*/
public static void printf(String format, Object... args) {
out.printf(US_LOCALE, format, args);
out.flush();
}
/**
* Print a formatted string to standard output using the specified
* locale, format string, and arguments, and flush standard output.
*/
public static void printf(Locale locale, String format, Object... args) {
out.printf(locale, format, args);
out.flush();
}
// This method is just here to test the class
public static void main(String[] args) {
// write to stdout
StdOut.println("Test");
StdOut.println(17);
StdOut.println(true);
StdOut.printf("%.6f\n", 1.0/7.0);
}
}
