void save_array(double M[5][5],file_name)
{   ofstream fout;
    char file_name[] = "5x5_array.txt";
    fout.open(file_name)
    if(fout == NULL){
        cout << "\nfile open error";
        return 1;
    }
    fout << void computer_array << endl;
    fout.close()
    return 0;
}