digraph_test.cpp

/******************************************************************************
 *
 * A directed graph, implemented using an array of sets. Parallel edges and self-loops allowed.
 *
 * Based on the source code from Robert Sedgewick and Kevin Wayne at https://algs4.cs.princeton.edu/
 *
 *  % ./digraph_test ../data/tinyDG.txt
 *  13 vertices, 22 edges
 *  0: 5 1
 *  1:
 *  2: 0 3
 *  3: 5 2
 *  4: 3 2
 *  5: 4
 *  6: 9 4 8 0
 *  7: 6 9
 *  8: 6
 *  9: 11 10
 *  10: 12
 *  11: 4 12
 *  12: 9
 *
 ******************************************************************************/

#include "digraph.h"

#include <fstream>
#include <iostream>

using namespace std;

// main entry point of the program
int main(int argc, char* argv[]) {
    // parameter check
    if (argc != 2) {
        cerr << "Invalid command line. Expecting one argument of input file name." << endl;
        return (1);
    }

    // read the digraph from the file
    ifstream graph_file;
    graph_file.open(argv[1]);
    if (!graph_file) {
        cerr << "Unable to open file " << argv[1] << endl;
        return (1);
    }
    Digraph dg(graph_file);
    graph_file.close();

    // output the digraph on the screen
    cout << dg << endl;

    return (0);
}