windows - C++ Can not create instance of abstract class -

i have following class:

(header)

struct udtmapping {     int bytestart;     int bytecount;     int ihpunitid; };  class clsmapping : public cbasestructure { private:     vector<udtmapping> m_content;  protected:  public:     vector<udtmapping> &content();     void add(int i1, int i2, int int3); }; 

cpp file:

 vector<udtmapping> &clsmapping::content()  {      return m_content;  }  void clsmapping::add(int i1, int i2,int i3)  {      udtmapping n;      n.bytestart = i1;      n.bytecount = i2;      n.ihpunitid  = i3;      m_content.push_back(n);          return;  } 

now wanted use class saying

clsmapping nmapping; 

but compiler tells me "can not create instance abstract class".

i not sure went wrong. thank help.

edit: on request here cbasestructure

 class cbasestructure   {  protected:      virtual void processtxtline(string line) = 0;      virtual void afterload();      virtual string compactline(string line);  public:      void load(string file);      void load2(string file);      void load3(string file);  }; 

cbasestructure must abstract class. if want derive , want non-abstract class must override each pure virtual function cbasestructure declares. didn't that.

edit

cbasestructure has 1 pure virtual function processtxtline. class must override function.

there nothing in code explains why inheriting cbasestructure, thing you?