C++ "not declared in this scope" error, with include files -

in code include following (this excerpt, make reader understand problem):

#include <iostream> #include <gsl/gsl_sf_gamma.h> #include <gsl/gsl_integration.h>  #include "metry.h" #include "growth.h"  #include <vector> using namespace std;  struct integral_params{     double = 1.;     double b = 1.; };   double f(double chizero, void* pp) {     integral_params *ip=static_cast<integral_params*>(pp);      params cp;      bool cls = true;     cosmo=new metry(cp);     structure=new growth(cp,cls); } 

at beginning of metry.h have

#ifndef metry_h #define metry_h  #include <gsl/gsl_spline.h> #include "cosmology.h"  class metry : public virtual cosmology 

which connected therefore cosmology.h, @ beginning of have

#ifndef cosmology_h #define cosmology_h  struct params {   //bla bla } 

and

class cosmology {  //bla bla } 

instead in growth.h have

#ifndef growth_h #define growth_h  #include <gsl/gsl_spline.h> #include "cosmology.h" #include "spectrum.h" 

and in spectrum.h

#ifndef spectrum_h #define spectrum_h  #include "cosmology.h" 

when compile following problem:

in function ‘double f(double, void*)’: : error: ‘cosmo’ not declared in scope      cosmo=new metry(cp);      ^~~~~ : error: ‘structure’ not declared in scope      structure=new growth(cp,cls);      ^~~~~~~~~ 

can me understand why logical order wrong in definitions , should fix this?

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