Dear all,
Context: I am developing a C++ API implementing Mimetic Finite Differences. An important class I am developing is the staggered grid representing my discrete domain:
I am starting simple: one spatial dimension.
For that I have created the MTK's Logically Rectangular One-Dimensional Uniform Staggered Grid class, or MTK_LR1DUniStgGrd.
Issue: I want to overload the ostream operator (<<) so that I can intuitively print the spatial values defining my grid.
Here's my header file:
[cpp]class MTK_LR1DUniStgGrd: public MTK_LR1DUniGrd {
friend ostream &operator<<(ostream &, const MTK_LR1DUniStgGrd &);
public:
MTK_LR1DUniStgGrd();
MTK_LR1DUniStgGrd(MTK_Real, MTK_Real, int);
virtual ~MTK_LR1DUniStgGrd();
void prt_array();
private:
MTK_Node *values_; //!< Collection of nodes.
int num_cells_; //!< Number of cell centers.
};[/cpp]
And this is the implementation in the source file:
[cpp]// An overloaded stream insertion operator cannot be a member function if we
// would like to invoke it with cout, e.g., cout << grid;
ostream& operator<<(ostream& output, const MTK_LR1DUniStgGrd& grid) {
//! Variables: 1
int ii; // Iterator.
//! MTK Classes:
MTK_Real aux_west_boundary;
MTK_Real aux_east_boundary;
MTK_Real aux_nodal_step_size;
MTK_Real aux_value_sub_ii;
//! Begin.
//! Validation stage:
if (grid.values_ == NULL) {
cerr << "Staggered grid can not be printed at " << __LINE__ - 1 << endl;
cerr << " of file " << __FILE__ << endl << flush;
cerr << "MTK: Terminating execution..." << endl << flush;
exit(EXIT_FAILURE);
}
//! Initialization stage:
aux_west_boundary = MTK_LR1DGrd::west_boundary_node();
aux_east_boundary = MTK_LR1DGrd::east_boundary_node();
aux_nodal_step_size = MTK_LR1DUniGrd::nodal_step_size();
output << "Staggered = [" << aux_west_boundary << ":" <<
aux_nodal_step_size<< ":" << aux_east_boundary << "] = " << endl << endl;
for (ii = 0; ii < (1 + grid.num_cells_ + 1); ii++) {
aux_value_sub_ii = (grid.values_[ii]).value();
output << setw(10) << aux_value_sub_ii << " ";
}
output << endl;
return output;
}[/cpp]
However, when building, I am getting the following output:
[bash]icpc -c -g -Iinclude -MMD -MP -MF build/Debug/Intel-Linux-x86/src/mtk_lr_1d_uni_stg_grd.o.d -o build/Debug/Intel-Linux-x86/src/mtk_lr_1d_uni_stg_grd.o src/mtk_lr_1d_uni_stg_grd.cc
src/mtk_lr_1d_uni_stg_grd.cc(73): error #308: member "mtk::MTK_LR1DUniStgGrd::values_" (declared at line 76 of "include/mtk_lr_1d_uni_stg_grd.h") is inaccessible
if (grid.values_ == NULL) {
^
src/mtk_lr_1d_uni_stg_grd.cc(81): error: a nonstatic member reference must be relative to a specific object
aux_west_boundary = MTK_LR1DGrd::west_boundary_node();
^
src/mtk_lr_1d_uni_stg_grd.cc(82): error: a nonstatic member reference must be relative to a specific object
aux_east_boundary = MTK_LR1DGrd::east_boundary_node();
^
src/mtk_lr_1d_uni_stg_grd.cc(83): error: a nonstatic member reference must be relative to a specific object
aux_nodal_step_size = MTK_LR1DUniGrd::nodal_step_size();
^
src/mtk_lr_1d_uni_stg_grd.cc(87): error #308: member "mtk::MTK_LR1DUniStgGrd::num_cells_" (declared at line 77 of "include/mtk_lr_1d_uni_stg_grd.h") is inaccessible
for (ii = 0; ii < (1 + grid.num_cells_ + 1); ii++) {
^
src/mtk_lr_1d_uni_stg_grd.cc(88): error #308: member "mtk::MTK_LR1DUniStgGrd::values_" (declared at line 76 of "include/mtk_lr_1d_uni_stg_grd.h") is inaccessible
aux_value_sub_ii = (grid.values_[ii]).value();
^
compilation aborted for src/mtk_lr_1d_uni_stg_grd.cc (code 2)[/bash]
As it can be seen, there are two kinds of problems that I am getting:
- Those related to the fact that the private members of the grid cannot be accessed, and
- Those related to invoking the base class to extract the values that I need, which I do not understand, since I have a public method called prt_array, which uses this code, and works.
Any hints?
Thanks in advanced! :D
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