open a csv file for testing but myfile.is_open() return false

I'm trying to open a csv file for testing but it always comes back to me "" Unable to open file "" and I can't figure out what I'm doing wrong. can anyone help me?

void testBSTWithInteger() {
    string line;
    ifstream myfile ("C:\\Users\\danie\\Desktop\\DatastructuresV2\\tests\\bstint.csv");
    if (myfile.is_open())
    {
        while ( getline (myfile,line) )
        {
            char c[line.length()];
            strcpy(c, line.c_str());
            auto bst = new BST<int>();

            for (int i= 0; i<line.length(); i++) {
                if (c[i] == 2) {
                    bst->insert(c[i]-48);
                    assert(bst->root->data == 2);
                    assert(bst->root->left == nullptr);
                }
                if (c[i] == 1) {
                    bst->insert(c[i]-48);
                    assert(bst->root->left->data == 1);
                }
                if (c[i] == 3) {
                    bst->insert(c[i]-48);
                    assert(bst->root->right->data == 3);
                    bst->deleteNode(2);
                    assert(bst->root->data == 3);
                    bst->deleteNode(3);
                    assert(bst->root->data == 1);
                    bst->deleteNode(1);
                    assert(bst->root == NULL);
                }
            }
        }
        myfile.close();
    }
    else cout << "Unable to open file";
}