c++ - Return Generic Type data from function -

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i have written following code. function func() print header , data.

class icell {     public:         wstring header;         virtual void fetch() = 0; };  template <class t> class cell : public icell { public:     //wstring header;     t data;     void fetch()     {         wcout<< header << l": ";         cout<<data<<endl;     }   // implementation of cell methods };  class row { public:   vector <icell *> cells; };

is there way return data instead of print within function? if so, portion of code should modified? in advance.

int main() {     cell<int>c1;     cell<double>c2;      c1.header = l"roll", c1.data = 100;     c2.header = l"cgpa", c2.data = 3.5;      row r;     r.cells.push_back(&c1);     r.cells.push_back(&c2);      vector <icell *>::iterator it;     for(it=r.cells.begin();it!=r.cells.end();it++)     {         //checkt type of wherther points cell<int> or cell<double>     }      return 0; }

i have changed question here. in main() inside loop how can check object type pointed 'it'?

thank patience , helping me :)

easiest way use dynamic_cast:

vector <icell *>::iterator it; for(it=r.cells.begin();it!=r.cells.end();it++) {     cell<int>* cell_i= dynamic_cast<cell<int>*>(*it);     if(cell_i)     {        do_something(cell_i->data);        continue;     }      cell<double>* cell_d= dynamic_cast<cell<double>*>(*it);     if(cell_d)     {        do_something(cell_d->data);        continue;     }  }

better way use visitor pattern:

class icellvisitor; //declaration icell understand icell* pointer class icell {   public:     ~icell(){}; // important     std::wstring header;     virtual void visit( icellvisitor* v ) = 0; }; template <class t> class cell; // cell<t>* pointer class icellvisitor {   public:     virtual void visit( cell<int>* c ) = 0;     virtual void visit( cell<double>* c ) = 0;     virtual void visit( cell<float>* c ) = 0;     virtual void visit( cell<long long>* c ) = 0; }; template <class t> class cell : public icell {   public:     //wstring header;     t data;     void visit( icellvisitor* v )     {         std::wcout<< header << l": ";         v->visit(this);     }   // implementation of cell methods }; class row { public:   std::vector <icell *> cells; };

now need definition of concrete visitor keep algorithm each type:

class mycellvisitor: public icellvisitor {   public:     void visit( cell<int>* c ){          std::wcout<<"(int)"<<c->data<<std::endl;      }     void visit( cell<double>* c ){          std::wcout<<"(double)"<<c->data<<std::endl;     }     void visit( cell<float>* c ){          std::wcout<<"(float)"<<c->data<<std::endl;     }     void visit( cell<long long>* c ){          std::wcout<<"(long long)"<<c->data<<std::endl;     } };  int main() {     cell<int>c1;     cell<double>c2;     c1.header = l"roll", c1.data = 100;     c2.header = l"cgpa", c2.data = 3.5;     row r;     r.cells.push_back(&c1);     r.cells.push_back(&c2);     mycellvisitor visitor;     std::vector <icell *>::iterator it;     for(it=r.cells.begin();it!=r.cells.end();it++)     {         (*it)->visit( &visitor );     }     return 0; }

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