#include <igraph.h>

int main(void) {

    igraph_t g;
    igraph_vector_int_t v1, v2;

    /* simple use */
    igraph_vector_int_init(&v1, 8);
    VECTOR(v1)[0] = 0;
    VECTOR(v1)[1] = 1;
    VECTOR(v1)[2] = 1;
    VECTOR(v1)[3] = 2;
    VECTOR(v1)[4] = 2;
    VECTOR(v1)[5] = 3;
    VECTOR(v1)[6] = 2;
    VECTOR(v1)[7] = 2;
    igraph_create(&g, &v1, 0, 0);
    if (igraph_vcount(&g) != 4) {
        return 1;
    }
    igraph_vector_int_init(&v2, 0);
    igraph_get_edgelist(&g, &v2, 0);
    igraph_vector_int_sort(&v1);
    igraph_vector_int_sort(&v2);
    if (!igraph_vector_int_all_e(&v1, &v2)) {
        return 2;
    }
    igraph_destroy(&g);

    /* higher number of vertices */
    igraph_create(&g, &v1, 10, 0);
    if (igraph_vcount(&g) != 10) {
        return 1;
    }
    igraph_get_edgelist(&g, &v2, 0);
    igraph_vector_int_sort(&v1);
    igraph_vector_int_sort(&v2);
    if (!igraph_vector_int_all_e(&v1, &v2)) {
        return 3;
    }
    igraph_destroy(&g);
    igraph_vector_int_destroy(&v1);
    igraph_vector_int_destroy(&v2);

    return 0;
}

#include <igraph.h>

int main(void) {

    igraph_t g;

    igraph_small(&g, 0, IGRAPH_DIRECTED, 0, 1, 1, 2, 2, 3, 3, 4, 6, 1, -1);
    igraph_write_graph_edgelist(&g, stdout);
    igraph_destroy(&g);

    return 0;
}

#include <igraph.h>

int main(void) {

    return 0;
}

#include <igraph.h>
#include <stdarg.h>

int main(void) {
    igraph_matrix_t mat;
    igraph_t g;
    int m[4][4] = { { 0, 1, 2, 0 }, { 2, 0, 0, 1 }, { 0, 0, 1, 0 }, { 0, 1, 0, 0 } };
    igraph_vector_t weights;
    igraph_vector_int_t el;
    igraph_integer_t i, j, n;
    igraph_vector_int_init(&el, 0);
    igraph_vector_init(&weights, 0);

    igraph_matrix_init(&mat, 4, 4);
    for (i = 0; i < 4; i++) for (j = 0; j < 4; j++) {
        MATRIX(mat, i, j) = m[i][j];
    }

    igraph_weighted_adjacency(&g, &mat, IGRAPH_ADJ_DIRECTED, &weights, IGRAPH_LOOPS_ONCE);

    igraph_get_edgelist(&g, &el, 0);
    n = igraph_ecount(&g);

    for (i = 0, j = 0; i < n; i++, j += 2) {
        printf("%" IGRAPH_PRId " --> %" IGRAPH_PRId ": %g\n",
               VECTOR(el)[j], VECTOR(el)[j + 1], VECTOR(weights)[i]);
    }

    igraph_matrix_destroy(&mat);
    igraph_vector_destroy(&weights);
    igraph_vector_int_destroy(&el);
    igraph_destroy(&g);

}

#include <igraph.h>
#include <stdio.h>

int main(void) {
    igraph_t graph;

    /* Create an undirected 6-star, with the 0th node as the centre. */
    igraph_star(&graph, 7, IGRAPH_STAR_UNDIRECTED, 0);

    /* Output the edge list of the graph. */
    igraph_write_graph_edgelist(&graph, stdout);

    /* Destroy the graph when we are done using it. */
    igraph_destroy(&graph);

    return 0;
}

#include <igraph.h>
#include <stdio.h>

int main(void) {
    igraph_t graph;

    /* Create a directed path graph on 10 vertices. */
    igraph_ring(&graph, 10, IGRAPH_DIRECTED, /* mutual= */ 0, /* circular= */ 0);

    /* Output the edge list of the graph. */
    printf("10-path graph:\n");
    igraph_write_graph_edgelist(&graph, stdout);

    /* Destroy the graph. */
    igraph_destroy(&graph);

    /* Create a 4-cycle graph. */
    igraph_ring(&graph, 4, IGRAPH_UNDIRECTED, /* mutual= */ 0, /* circular= */ 1);

    /* Output the edge list of the graph. */
    printf("\n4-cycle graph:\n");
    igraph_write_graph_edgelist(&graph, stdout);

    /* Destroy the graph. */
    igraph_destroy(&graph);

    return 0;
}

#include <igraph.h>

int main(void) {
    igraph_t graph;
    igraph_bool_t res;

    /* Create a directed binary tree on 15 nodes,
       with edges pointing towards the root. */
    igraph_kary_tree(&graph, 15, 2, IGRAPH_TREE_IN);

    igraph_is_tree(&graph, &res, NULL, IGRAPH_IN);
    printf("Is it an in-tree? %s\n", res ? "Yes" : "No");

    igraph_is_tree(&graph, &res, NULL, IGRAPH_OUT);
    printf("Is it an out-tree? %s\n", res ? "Yes" : "No");

    igraph_destroy(&graph);

    return 0;
}

#include <igraph.h>

int main(void) {

    igraph_t graph;
    igraph_bool_t res;
    igraph_vector_int_t v;
    igraph_vector_int_init_int(&v, 3, 3, 4, 5);

    /* Create a directed symmetric tree with 2 levels -
       3 children in first and 4 children in second level,
       5 children in third level
       with edges pointing towards the root. */
    igraph_symmetric_tree(&graph, &v, IGRAPH_TREE_IN);

    igraph_is_tree(&graph, &res, NULL, IGRAPH_IN);
    printf("Is it an in-tree? %s\n", res ? "Yes" : "No");

    igraph_is_tree(&graph, &res, NULL, IGRAPH_OUT);
    printf("Is it an out-tree? %s\n", res ? "Yes" : "No");

    igraph_destroy(&graph);
    igraph_vector_int_destroy(&v);

    return 0;
}

#include <igraph.h>

int main(void) {
    igraph_t tree;
    igraph_vector_t eccentricity;
    igraph_bool_t is_tree;

    /* Create a Bethe lattice with 5 levels, i.e. height 4. */
    igraph_regular_tree(&tree, 4, 3, IGRAPH_TREE_UNDIRECTED);

    /* Bethe lattices are trees. */
    igraph_is_tree(&tree, &is_tree, NULL, IGRAPH_ALL);
    printf("Is it a tree? %s\n", is_tree ? "Yes." : "No.");

    /* Compute and print eccentricities. The root is the most central. */
    igraph_vector_init(&eccentricity, 0);
    igraph_eccentricity(&tree, &eccentricity, igraph_vss_all(), IGRAPH_ALL);
    printf("Vertex eccentricities:\n");
    igraph_vector_print(&eccentricity);
    igraph_vector_destroy(&eccentricity);

    /* Clean up. */
    igraph_destroy(&tree);

    return 0;
}

#include <igraph.h>
#include <stdio.h>

int main(void) {
    igraph_t graph;
    igraph_integer_t n_vertices = 10;

    /* Create an undirected complete graph. */
    /* Use IGRAPH_UNDIRECTED and IGRAPH_NO_LOOPS instead of 1/TRUE and 0/FALSE for better readability. */
    igraph_full(&graph, n_vertices, IGRAPH_UNDIRECTED, IGRAPH_NO_LOOPS);
    printf("The undirected complete graph on %" IGRAPH_PRId " vertices has %" IGRAPH_PRId " edges.\n",
          igraph_vcount(&graph), igraph_ecount(&graph));

    /* Remember to destroy the object at the end. */
    igraph_destroy(&graph);

    /* Create a directed complete graph. */
    igraph_full(&graph, n_vertices, IGRAPH_DIRECTED, IGRAPH_NO_LOOPS);
    printf("The directed complete graph on %" IGRAPH_PRId " vertices has %" IGRAPH_PRId " edges.\n",
          igraph_vcount(&graph), igraph_ecount(&graph));

    igraph_destroy(&graph);

    /* Create an undirected complete graph with self-loops. */
    igraph_full(&graph, n_vertices, IGRAPH_UNDIRECTED, IGRAPH_LOOPS);
    printf("The undirected complete graph on %" IGRAPH_PRId " vertices with self-loops has %" IGRAPH_PRId " edges.\n",
          igraph_vcount(&graph), igraph_ecount(&graph));

    igraph_destroy(&graph);

    /* Create a directed graph with self-loops. */
    igraph_full(&graph, n_vertices, IGRAPH_DIRECTED, IGRAPH_LOOPS);
    printf("The directed complete graph on %" IGRAPH_PRId " vertices with self-loops has %" IGRAPH_PRId " edges.\n",
          igraph_vcount(&graph), igraph_ecount(&graph));

    igraph_destroy(&graph);

    return 0;

}

#include <igraph.h>
#include <stdio.h>

int main(void){
    igraph_t g1, g2, g3;
    igraph_integer_t nodes = 500, A = 0, power = 1, m = 1;
    igraph_real_t assortativity;

    igraph_rng_seed(igraph_rng_default(), 42);
    printf("Demonstration of difference in assortativities of graphs with the same degree sequence but different linkages:\n\nInitial graph based on the Barabasi-Albert model with %" IGRAPH_PRId " nodes.\n", nodes);

    /* Graph 1 generated by a randomized graph generator */
    igraph_barabasi_game(&g1, nodes, power, m, NULL, /* outpref */ 0, A, IGRAPH_UNDIRECTED, IGRAPH_BARABASI_PSUMTREE, /* start from */ NULL);

    igraph_vector_int_t degree;
    igraph_vector_int_init(&degree, nodes);
    igraph_degree(&g1, &degree, igraph_vss_all(), IGRAPH_ALL, IGRAPH_NO_LOOPS);

    /* Measuring assortativity of the first graph */
    igraph_assortativity_degree(&g1, &assortativity, IGRAPH_UNDIRECTED);
    printf("Assortativity of initial graph = %g\n\n", assortativity);
    igraph_destroy(&g1);

    /* Graph 2 (with the same degree sequence) generated by selecting vertices with the smallest degree first */
    igraph_realize_degree_sequence(&g2, &degree, NULL, IGRAPH_SIMPLE_SW, IGRAPH_REALIZE_DEGSEQ_SMALLEST);
    igraph_assortativity_degree(&g2, &assortativity, IGRAPH_UNDIRECTED);
    printf("Assortativity after choosing vertices with the smallest degrees first = %g\n\n", assortativity);
    igraph_destroy(&g2);

    /* Graph 3 (with the same degree sequence) generated by selecting vertices with the largest degree first */
    igraph_realize_degree_sequence(&g3, &degree, NULL, IGRAPH_SIMPLE_SW, IGRAPH_REALIZE_DEGSEQ_LARGEST);
    igraph_assortativity_degree(&g3, &assortativity, IGRAPH_UNDIRECTED);
    printf("Assortativity after choosing vertices with the largest degrees first = %g\n", assortativity);
    igraph_destroy(&g3);
    igraph_vector_int_destroy(&degree);

    return 0;
}

#include <igraph.h>

int main(void) {

    igraph_t g, g2;
    igraph_bool_t iso;

    // Franklin graph
    igraph_lcf(&g, 12, 5, -5, 6, 0);
    igraph_famous(&g2, "franklin");

    igraph_isomorphic_vf2(&g, &g2,
                          /*vertex.color1=*/ 0, /*vertex.color2=*/ 0,
                          /*edge.color1=*/ 0, /*edge.color2=*/ 0,
                          &iso, 0, 0, 0, 0, 0);
    if (!iso) {
        printf("Failure: Franklin\n");
        return 1;
    }

    igraph_destroy(&g);
    igraph_destroy(&g2);

    // [3, -2]^4, n=8
    igraph_lcf(&g, 8, 3, -2, 4, 0);

    if (igraph_ecount(&g) != 16) {
        printf("Failure: [3, -2]^4, n=8\n");
        return 1;
    }

    igraph_destroy(&g);

    // [2, -2]^2, n=2
    igraph_lcf(&g, 2, 2, -2, 2, 0);

    if (igraph_ecount(&g) != 1) {
        printf("Failure: [2, -2]^2, n=2\n");
        return 1;
    }

    igraph_destroy(&g);

    // [2]^2, n=2
    igraph_lcf(&g, 2, 2, 2, 0);

    if (igraph_ecount(&g) != 1) {
        printf("Failure: [2]^2, n=2\n");
        return 1;
    }

    igraph_destroy(&g);

    // Regression test for bug #996
    igraph_lcf(&g, 0, 0);
    if (igraph_vcount(&g) != 0 || igraph_ecount(&g) != 0) {
        printf("Failure: regression test for #996\n");
        return 1;
    }

    igraph_destroy(&g);

    return 0;
}

#include <igraph.h>

int main(void) {

    igraph_t g;

    igraph_atlas(&g, 45);
    igraph_write_graph_edgelist(&g, stdout);
    printf("\n");
    igraph_destroy(&g);

    igraph_atlas(&g, 0);
    igraph_write_graph_edgelist(&g, stdout);
    printf("\n");
    igraph_destroy(&g);

    igraph_atlas(&g, 1252);
    igraph_write_graph_edgelist(&g, stdout);
    printf("\n");
    igraph_destroy(&g);

    return 0;
}

#include <igraph.h>
#include <math.h>

int main(void) {
    igraph_t graph;
    igraph_vector_t x, y;
    igraph_vector_t weights;
    igraph_eit_t eit;
    igraph_real_t avg_dist;

    /* Set random seed for reproducible results */

    igraph_rng_seed(igraph_rng_default(), 42);

    /* Create a random geometric graph and retrieve vertex coordinates */

    igraph_vector_init(&x, 0);
    igraph_vector_init(&y, 0);

    igraph_grg_game(&graph, 200, 0.1, /* torus */ 0, &x, &y);

    /* Compute edge weights as geometric distance */

    igraph_vector_init(&weights, igraph_ecount(&graph));
    igraph_eit_create(&graph, igraph_ess_all(IGRAPH_EDGEORDER_ID), &eit);
    for (; ! IGRAPH_EIT_END(eit); IGRAPH_EIT_NEXT(eit)) {
        igraph_integer_t e = IGRAPH_EIT_GET(eit);
        igraph_integer_t u = IGRAPH_FROM(&graph, e);
        igraph_integer_t v = IGRAPH_TO(&graph, e);

        VECTOR(weights)[e] = hypot(VECTOR(x)[u] - VECTOR(x)[v], VECTOR(y)[u] - VECTOR(y)[v]);
    }
    igraph_eit_destroy(&eit);

    /* Compute average path length */

    igraph_average_path_length_dijkstra(&graph, &avg_dist, NULL, &weights, IGRAPH_UNDIRECTED, /* unconn */ 1);

    printf("Average distance in the geometric graph: %g.\n", avg_dist);

    /* Destroy data structures when no longer needed */

    igraph_vector_destroy(&weights);
    igraph_destroy(&graph);
    igraph_vector_destroy(&x);
    igraph_vector_destroy(&y);

    return 0;
}

#include <igraph.h>

int main(void) {

    igraph_t g;
    igraph_vector_int_t v;
    igraph_vector_int_t v2, v3;

    igraph_barabasi_game(&g, 10, /*power=*/ 1, 2, 0, 0, /*A=*/ 1, 1,
                         IGRAPH_BARABASI_BAG, /*start_from=*/ 0);
    if (igraph_ecount(&g) != 18) {
        return 1;
    }
    if (igraph_vcount(&g) != 10) {
        return 2;
    }
    if (!igraph_is_directed(&g)) {
        return 3;
    }

    igraph_vector_int_init(&v, 0);
    igraph_get_edgelist(&g, &v, 0);
    for (igraph_integer_t i = 0; i < igraph_ecount(&g); i++) {
        if (VECTOR(v)[2 * i] <= VECTOR(v)[2 * i + 1]) {
            return 4;
        }
    }
    igraph_vector_int_destroy(&v);
    igraph_destroy(&g);

    /* out-degree sequence */
    igraph_vector_int_init_int(&v3, 10, 0, 1, 3, 3, 4, 5, 6, 7, 8, 9);

    igraph_barabasi_game(&g, 10, /*power=*/ 1, 0, &v3, 0, /*A=*/ 1, 1,
                         IGRAPH_BARABASI_BAG, /*start_from=*/ 0);
    if (igraph_ecount(&g) != igraph_vector_int_sum(&v3)) {
        return 5;
    }
    igraph_vector_int_init(&v2, 0);
    igraph_degree(&g, &v2, igraph_vss_all(), IGRAPH_OUT, 1);
    for (igraph_integer_t i = 0; i < igraph_vcount(&g); i++) {
        if (VECTOR(v3)[i] != VECTOR(v2)[i]) {
            igraph_vector_int_print(&v3);
            printf("\n");
            igraph_vector_int_print(&v2);
            return 6;
        }
    }
    igraph_vector_int_destroy(&v3);
    igraph_vector_int_destroy(&v2);
    igraph_destroy(&g);

    /* outpref, we cannot really test this quantitatively,
       would need to set random seed */
    igraph_barabasi_game(&g, 10, /*power=*/ 1, 2, 0, 1, /*A=*/ 1, 1,
                         IGRAPH_BARABASI_BAG, /*start_from=*/ 0);
    igraph_vector_int_init(&v, 0);
    igraph_get_edgelist(&g, &v, 0);
    for (igraph_integer_t i = 0; i < igraph_ecount(&g); i++) {
        if (VECTOR(v)[2 * i] <= VECTOR(v)[2 * i + 1]) {
            return 7;
        }
    }
    if (!igraph_is_directed(&g)) {
        return 8;
    }
    igraph_vector_int_destroy(&v);
    igraph_destroy(&g);

    return 0;
}

#include <igraph.h>
#include <stdio.h>

int main(void) {

    igraph_t g;
    igraph_bool_t simple;

    igraph_barabasi_game(/* graph=    */ &g,
                                         /* n=        */ 100,
                                         /* power=    */ 1.0,
                                         /* m=        */ 2,
                                         /* outseq=   */ 0,
                                         /* outpref=  */ 0,
                                         /* A=        */ 1.0,
                                         /* directed= */ IGRAPH_DIRECTED,
                                         /* algo=     */ IGRAPH_BARABASI_PSUMTREE,
                                         /* start_from= */ 0);

    if (igraph_ecount(&g) != 197) {
        return 1;
    }
    if (igraph_vcount(&g) != 100) {
        return 2;
    }
    igraph_is_simple(&g, &simple);
    if (!simple) {
        return 3;
    }

    igraph_destroy(&g);

    /* ============================== */

    igraph_barabasi_game(/* graph=    */ &g,
                                         /* n=        */ 100,
                                         /* power=    */ 1.0,
                                         /* m=        */ 2,
                                         /* outseq=   */ 0,
                                         /* outpref=  */ 0,
                                         /* A=        */ 1.0,
                                         /* directed= */ IGRAPH_DIRECTED,
                                         /* algo=     */ IGRAPH_BARABASI_PSUMTREE_MULTIPLE,
                                         /* start_from= */ 0);

    if (igraph_ecount(&g) != 198) {
        return 4;
    }
    if (igraph_vcount(&g) != 100) {
        return 5;
    }
    igraph_is_simple(&g, &simple);
    if (simple) {
        return 6;
    }

    igraph_destroy(&g);

    /* ============================== */

    igraph_barabasi_game(/* graph=    */ &g,
                                         /* n=        */ 100,
                                         /* power=    */ 1.0,
                                         /* m=        */ 2,
                                         /* outseq=   */ 0,
                                         /* outpref=  */ 0,
                                         /* A=        */ 1.0,
                                         /* directed= */ IGRAPH_DIRECTED,
                                         /* algo=     */ IGRAPH_BARABASI_BAG,
                                         /* start_from= */ 0);

    if (igraph_ecount(&g) != 198) {
        return 7;
    }
    if (igraph_vcount(&g) != 100) {
        return 8;
    }
    igraph_is_simple(&g, &simple);
    if (simple) {
        return 9;
    }

    igraph_destroy(&g);

    return 0;
}

#include <igraph.h>

int main(void) {
    igraph_t graph;
    igraph_vector_int_t component_sizes;

    igraph_rng_seed(igraph_rng_default(), 42); /* make program deterministic */

    /* Sample a graph from the Erdős-Rényi G(n,m) model */

    igraph_erdos_renyi_game_gnm(
        &graph, /* n= */ 100, /* m= */ 100,
        IGRAPH_UNDIRECTED, IGRAPH_NO_LOOPS
    );

    /* Compute the fraction of vertices contained within the largest connected component */

    igraph_vector_int_init(&component_sizes, 0);
    igraph_connected_components(&graph, NULL, &component_sizes, NULL, IGRAPH_STRONG);

    printf(
        "Fraction of vertices in giant component: %g\n",
        ((double) igraph_vector_int_max(&component_sizes)) / igraph_vcount(&graph)
    );

    /* Clean up data structures when no longer needed */

    igraph_vector_int_destroy(&component_sizes);
    igraph_destroy(&graph);

    return 0;
}

#include <igraph.h>

int main(void) {
    igraph_t graph;
    igraph_vector_int_t component_sizes;

    igraph_rng_seed(igraph_rng_default(), 42); /* make program deterministic */

    /* Sample a graph from the Erdős-Rényi G(n,p) model */

    igraph_erdos_renyi_game_gnp(
        &graph, /* n= */ 100, /* p= */ 0.01,
        IGRAPH_UNDIRECTED, IGRAPH_NO_LOOPS
    );

    /* Compute the fraction of vertices contained within the largest connected component */

    igraph_vector_int_init(&component_sizes, 0);
    igraph_connected_components(&graph, NULL, &component_sizes, NULL, IGRAPH_STRONG);

    printf(
        "Fraction of vertices in giant component: %g\n",
        ((double) igraph_vector_int_max(&component_sizes)) / igraph_vcount(&graph)
    );

    /* Clean up data structures when no longer needed */

    igraph_vector_int_destroy(&component_sizes);
    igraph_destroy(&graph);

    return 0;
}

#include <igraph.h>

int main(void) {
    igraph_t g;
    igraph_vector_int_t outdeg, indeg;
    igraph_vector_int_t vec;
    igraph_bool_t is_simple;

    /* Set random seed for reproducibility */
    igraph_rng_seed(igraph_rng_default(), 42);

    igraph_vector_int_init_int(&outdeg, 10, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3);
    igraph_vector_int_init_int(&indeg, 10, 4, 4, 2, 2, 4, 4, 2, 2, 3, 3);
    igraph_vector_int_init(&vec, 0);

    /* checking the configuration model, undirected graphs */
    igraph_degree_sequence_game(&g, &outdeg, 0, IGRAPH_DEGSEQ_CONFIGURATION);
    if (igraph_is_directed(&g) || igraph_vcount(&g) != 10) {
        return 1;
    }
    if (igraph_degree(&g, &vec, igraph_vss_all(), IGRAPH_OUT, 1)) {
        return 2;
    }
    igraph_vector_int_print(&vec);
    igraph_destroy(&g);

    /* checking the Viger-Latapy method, undirected graphs */
    igraph_degree_sequence_game(&g, &outdeg, 0, IGRAPH_DEGSEQ_VL);
    if (igraph_is_directed(&g) || igraph_vcount(&g) != 10) {
        return 3;
    }
    if (igraph_is_simple(&g, &is_simple) || !is_simple) {
        return 4;
    }
    if (igraph_degree(&g, &vec, igraph_vss_all(), IGRAPH_OUT, 0)) {
        return 5;
    }
    igraph_vector_int_print(&vec);
    igraph_destroy(&g);

    /* checking the configuration model, directed graphs */
    igraph_degree_sequence_game(&g, &outdeg, &indeg, IGRAPH_DEGSEQ_CONFIGURATION);
    if (!igraph_is_directed(&g) || igraph_vcount(&g) != 10) {
        return 6;
    }
    if (igraph_degree(&g, &vec, igraph_vss_all(), IGRAPH_OUT, 1)) {
        return 7;
    }
    igraph_vector_int_print(&vec);
    if (igraph_degree(&g, &vec, igraph_vss_all(), IGRAPH_IN, 1)) {
        return 8;
    }
    igraph_vector_int_print(&vec);
    igraph_destroy(&g);

    /* checking the fast heuristic method, undirected graphs */
    igraph_degree_sequence_game(&g, &outdeg, 0, IGRAPH_DEGSEQ_FAST_HEUR_SIMPLE);
    if (igraph_is_directed(&g) || igraph_vcount(&g) != 10) {
        return 9;
    }
    if (igraph_is_simple(&g, &is_simple) || !is_simple) {
        return 10;
    }
    if (igraph_degree(&g, &vec, igraph_vss_all(), IGRAPH_OUT, 1)) {
        return 11;
    }
    igraph_vector_int_print(&vec);
    igraph_destroy(&g);

    /* checking the fast heuristic method, directed graphs */
    igraph_degree_sequence_game(&g, &outdeg, &indeg, IGRAPH_DEGSEQ_FAST_HEUR_SIMPLE);
    if (!igraph_is_directed(&g) || igraph_vcount(&g) != 10) {
        return 12;
    }
    if (igraph_is_simple(&g, &is_simple) || !is_simple) {
        return 13;
    }
    if (igraph_degree(&g, &vec, igraph_vss_all(), IGRAPH_OUT, 1)) {
        return 14;
    }
    igraph_vector_int_print(&vec);
    if (igraph_degree(&g, &vec, igraph_vss_all(), IGRAPH_IN, 1)) {
        return 15;
    }
    igraph_vector_int_print(&vec);
    igraph_destroy(&g);

    igraph_vector_int_destroy(&vec);
    igraph_vector_int_destroy(&outdeg);
    igraph_vector_int_destroy(&indeg);

    return 0;
}