Graph [Matrix Representation]

class Graph
{
    int **adjacentMatrix;
    int _vertexCount;

    void init();

public:
    Graph(int);
    ~Graph();

    void addEdgeUndirected(int, int);
    void addEdgeUndirected(int, int, int);

    void addEdgeDirected(int, int);
    void addEdgeDirected(int, int, int);

    void removeEdgeUndirected(int, int);
    void removeEdgeDirected(int, int);

    bool hasEdgeBetween(int, int);
    int getVertexCount();
    Graph* getTranspose_Matrix();
    void display();
};

Graph::Graph(int count)
{
    this->_vertexCount = count;
    init();
}

Graph::~Graph()
{
    for (int i = 0; i < _vertexCount; ++i)
    {
        delete[] this->adjacentMatrix[i];
    }
    delete[] this->adjacentMatrix;
}

void Graph::init()
{
    adjacentMatrix = new int*[this->_vertexCount];
    for (int i = 0; i < _vertexCount; ++i)
    {
        adjacentMatrix[i] = new int[this->_vertexCount]{ 0 };
    }
}

void Graph::addEdgeUndirected(int i, int j, int cost)
{
    this->adjacentMatrix[i][j] = cost;
    this->adjacentMatrix[j][i] = cost;
}

void Graph::addEdgeUndirected(int i, int j)
{
    this->addEdgeUndirected(i, j, 1);
}

void Graph::removeEdgeUndirected(int i, int j)
{
    this->addEdgeUndirected(i, j, 0);
}

void Graph::addEdgeDirected(int i, int j, int cost)
{
    this->adjacentMatrix[i][j] = cost;
}

void Graph::addEdgeDirected(int i, int j)
{
    this->addEdgeDirected(i, j, 1);
}

void Graph::removeEdgeDirected(int i, int j)
{
    this->addEdgeDirected(i, j, 0);
}

bool Graph::hasEdgeBetween(int i, int j)
{
    return this->adjacentMatrix[i][j] == 1;
}

int Graph::getVertexCount()
{
    return this->_vertexCount;
}

Graph* Graph::getTranspose_Matrix()
{
    Graph* gT = new Graph(this->_vertexCount);

    for (int i = 0; i < this->_vertexCount; ++i)
    {
        for (int j = 0; j < _vertexCount; ++j)
        {
            gT->adjacentMatrix[i][j] = this->adjacentMatrix[j][i];
        }
    }
    return gT;
}

void Graph::display()
{
    cout << "\nGraph in Matrix:\n----------------\n";
    for (int i = 0; i < this->_vertexCount; ++i)
    {
        for (int j = 0; j < this->_vertexCount; ++j)
        {
            cout << this->adjacentMatrix[i][j] << " ";
        }
        cout << endl;
    }
}