Can't display Dynamic 2D array

[heybronson]

Hello, I'm unable to print my 2D array. When entering the for loop in display(), my program seems to run continuously, without an error message. Everything compiles fine and I can't seem to find what is causing this issue. Below is the header file along with the display and load functions.

Graph.h:
class Graph{

public:
Graph(); // constructor
~Graph(); // destructor

// Load the graph from a file
void load(char *filename);

// Display the adjacency matrix
void display() const;

// Display the depth first search from the given vertex
void displayDFS(int vertex) const;

// Display the breadth first search from the given vertex
void displayBFS(int vertex) const;

// Determine whether the graph is bipartite or not
bool isBipartite() const;

private:
// TODO: Complete the private section of the class.
int **arr;
int vertices;
void DFS(int vertex, bool *marked) const;
};

Graph.cpp:
Graph::Graph(){
}

// Destructor
Graph::~Graph(){
for(int i = 0; i < vertices; i++)
delete arr[i];
delete arr;
}

// Load the graph from a file
void Graph::load(char *filename){
ifstream file;
file.open(filename);
int x, y;

file >> vertices;
cout << "vertices: " << vertices << endl;
int **arr = new int*[vertices];
for(int i = 0; i < vertices; i++){
arr[i] = new int[vertices]();
}

while(file >> x >> y){
arr[x][y] = 1;
arr[y][x] = 1;
cout << "adding vertex" << x << y << endl;
}
//cout << "finish load" << endl;
//cout << arr[0][1] << endl;
//cout << arr[0][0] << endl;
}

// Display the adjacency matrix
void Graph::display() const{
//cout << "starting display" << endl;

for(int i = 0; i < vertices; i++){
for(int j = 0; j < vertices; j++)
cout << arr[i][j] << " ";
cout << endl;
}
//cout << "finish display" << endl;
}

Thank you.

[jonnin]

can we assume you load, then print, and nothing in the middle?

[heybronson]

Yes I go directly from loading a graph to printing it. I have found that the error is a segmentation fault somewhere, but I can't seem to find it.

[heybronson]

This is a cleaner view:

In Graph.h:

private:
// TODO: Complete the private section of the class.
int **arr;
int vertices ;
void DFS(int vertex, bool *marked) const;

In Graph.cpp:

void Graph::load(char *filename){
ifstream file;
file.open(filename);
int x, y;

file >> vertices;
cout << "vertices: " << vertices << endl;
int **arr = new int*[vertices];
for(int i = 0; i < vertices; i++){
arr[i] = new int[vertices];
}

for(int i = 0; i < vertices; i++){
for(int j = 0; j < vertices; j++)
arr[i][j] = 0;
}

while(file >> x >> y){
arr[x][y] = 1;
arr[y][x] = 1;
cout << "adding vertex" << x << y << endl;
}
file.close();
}

// Display the adjacency matrix
void Graph::display() const{

for(int i = 0; i < vertices; i++){
for(int j = 0; j < vertices; j++)
cout << arr[i][j] << " ";
cout << endl;
}
}