output incorrect matrix determinant

I have been writing a matrix class that calculates the determinant of any n x m input matrix using 1D dynamic array (single pointer), however I am getting incorrect outputs and I can not seem to see my problem, here is my determinant member function (the member function da_minorM calculates the minor matrices):

double dymatrix::da_det(dymatrix & arr , int o_O)   //determinant
{
    o_O = arr.columns;
    double det(0);
    dymatrix Minor (arr.rows-1,arr.columns-1);
    for (int i = 1; i <=o_O; i++)
    {
            //cout<<"i "<<i<<endl;
        if (o_O == 1)
        {
            det+=matrix[0];
        }
        Minor = da_minorM(arr,1,i);
        cout<<"Minor "<<Minor<<endl;
        cout<<"arr "<<arr.matrix[0]<<endl;
        det += pow(-1,i-1)*matrix[i-1]*da_det(Minor, o_O-1);
        cout<<"i "<<i<<endl;
    }
    if (rows !=columns)
    {
        cerr<<"SIZE DO NOT MATCH, YOU FAIL"<<endl; exit(1);
    }
return det;
}

I have overloaded "( )" and "[ ]" operators here:

double & operator[](const int n)    
{
    if(n<0 || n>=rows*columns)
    {
        cout<<"Error: trying to access matrix element out of bounds"<<endl<<" n "<<n<<" size "<<rows*columns<<endl<<endl;
        exit(1);
    }
return matrix[n];

} 

int index(int j, int i) const //This member function returns the position of each index.
{
    if (j > 0 && j <=rows && i > 0 && i <=columns)
    {
        //cout<<"i is "<<i<<" j is "<<j<<endl<<endl<<"row is "<<rows<<" columns is "<<columns<<endl;
        return (i-1)+(j-1)*columns;
    }
    else {cout<<"Error, out of range"<<endl<<"i is "<<i<<" j is "<<j<<endl<<endl<<"row is "<<rows<<" columns is "<<columns<<endl; exit (1);}
}
//Overloading "**()**" operator.    
double & operator()(int j, int i) const {return matrix[index(j,i)];} 

The "index" member function converts the location of elements in 2D matrix to 1D matrix location.

This is my da_minorM matrix member function which calculates the minor matrices not minors:

dymatrix dymatrix::da_minorM(dymatrix &arr, int c, int r)   //This calculates the minor matrix of any given indices.
{
    dymatrix new_matrix(arr.rows-1,arr.columns-1); //This creates a new matrix which has a dimension of the rows -1 and columns -1 of the input matrix.
    int ic =0;  //Initialise the counter;
    for (int j = 1; j<=arr.rows; j++)   //The loop starts from the first row.
    {
        if(j != r ) //The loop will continue only if the row number is not equal to the row number that the user wishes to delete.
        {       
            for (int i = 1; i <=arr.columns; i++)   //This goes through the column elements.
            {
                if (i != c) //Again the loop will continue only if the column number is not equal to the column number that the user wishes to delete.
                {   
                    new_matrix[ic] = arr(j,i);  //After the conditions above, the residual matrix should be the minor matrix of any element based on users choice.
                    ic++;   //This ic counter will go through the 1D array element by element, as "[]" operator was overloaded above.
                }   
            }
        }
    }
    return new_matrix;  //This returns the matrix.
    if(columns !=rows)
    {
    cerr<<"Row and Columns must have same dimention"<<endl;
    }
}

I found my error, I misplaced rows and columns (silly me :D) at

Minor = da_minorM(arr,1,i);

where I defined

da_minorM(array, columns, rows)

so instead I should have

Minor = da_minorM(arr,i,1);

Thanks for all the help