// open file
fstream file(file_name, ios::in | ios::binary);

int vertices_count = 0;
long long edges_count = 0;

// read header
file.read((char*)(&vertices_count), sizeof(int));
file.read((char*)(&edges_count), sizeof(long long));

// print graph
cout << "Graph has " << vertices_count << " vertices" << endl;
cout << "Graph has " << edges_count << " edges" << endl;

// get & print graph data for WEIGHTED graph
for(long long i = 0; i < edges_count; i++){
    int src_id = 0, dst_id = 0;
    float weight = 0;

    // read i-th edge data
    file.read((char*)(&src_id), sizeof(int));
    file.read((char*)(&dst_id), sizeof(int));
    file.read((char*)(&weight), sizeof(float)); // remove it for unweighed graph

    //print edge data
    cout << src_id << " " << dst_id << " | " << weight << endl;
}

file.close();