main() undirected

public static void main(String[] args) throws FileNotFoundException {

    /* Manually create a graph */
    Graph g1 = new Graph(5);
    g1.addEdge(1, 0);
    g1.addEdge(1, 2);
    g1.addEdge(2, 0);
    g1.addEdge(0, 3);
    g1.addEdge(3, 4);

    System.out.println("Number of vertices: " + g1.V());    // 5
    System.out.println("Number of edges: " + g1.E());       // 5

    /* See adjacent vertices of vertex 0 */
    /* Expected: 1, 2, 3 */
    System.out.println("Adjacent vertices of 0 (manual): ");
    Iterable<Integer> vertices1 = g1.adj(0);
    for (Integer v: vertices1) {
        System.out.println(v);
    }

    System.out.println();

    /* Read a graph from a file */
    Graph g2 = new Graph(new Scanner(new File("/home/aldin-sxr/Downloads/tinyG.txt")));

    System.out.println("Number of vertices: " + g2.V());    // 13
    System.out.println("Number of edges: " + g2.E());       // 13

    /* See adjacent vertices of vertex 0 */
    /* Expected: 5, 1, 2, 6 */
    System.out.println("Adjacent vertices of 0 (file): ");
    Iterable<Integer> vertices2 = g2.adj(0);
    for (Integer v: vertices2) {
        System.out.println(v);
    }
}