Define a class Digraph containing lists of vertices and edges and a class AdjacencyMatrix where a 1 indicates an edge between subscript vertices. Include constructors for automatic conversion.

Question

What will be an ideal response?

Answer 1

```
onst int MAX_VERTICES = 6;
const int MAX_EDGES = MAX_VERTICES * MAX_VERTICES;

class Digraph;
class AdjacencyMatrix { // Represents a varying-size matrix that
// can be input from a file
public:
AdjacencyMatrix() {}
AdjacencyMatrix( const Digraph& ); // Constructor that initializes a
// matrix from a digraph
int getN() const; // Accessors
int getValue(int, int) const;

private:
int n;
int mat[MAX_VERTICES][MAX_VERTICES];

friend ostream& operator<< ( ostream&, const AdjacencyMatrix& );
friend istream& operator>> ( istream&, AdjacencyMatrix& );
};

class Digraph { // Represents a list of n vertices and varying number
// of edges connecting those vertices
public:
Digraph() {}
Digraph( const AdjacencyMatrix& ); // Constructor that initializes a
// digraph from an adjacency matrix
int getN() const; // Accessors
int getNumEdges() const;
void getEdge(const int, int&, int&) const;

private:
int n; // n vertices
int numEdges; // number of edges
int edges[MAX_EDGES][2]; // vertex pairs

friend ostream& operator<< ( ostream&, const Digraph& );
friend istream& operator>> ( istream&, Digraph& );
};

int main()
{
AdjacencyMatrix m1,m2;
Digraph d1,d2;
string infilename1, infilename2;

cout << endl << "Enter the Adjacency Matrix input file name => ";
cin >> infilename1;
ifstream infile1(infilename1.c_str(), ios::in);
cout << endl << "Enter the Digraph input file name => ";
cin >> infilename2;
ifstream infile2(infilename2.c_str(), ios::in);

infile1 >> m1;
infile2 >> d1;
m2 = AdjacencyMatrix(d1);
d2 = Digraph(m1);

cout << endl << "Adjacency Matrix entered:" << endl << m1;
cout << endl << "Digraph computed:" << endl << d2;
cout << endl << "Digraph entered:" << endl << d1;
cout << endl << "Adjacency Matrix computed:" << endl << m2;
cout << endl;

return 0;
}

```