Sar.h
class Sar
{
 private:
  Elem *pr, *akt;
  Sar(const Sar&);
  void operator =(const Sar&);
 public:
  Sar():pr(NULL), akt(NULL){}


  void Skaityti(char *fv);

};


Unit1.cpp
#include "Sar.h"
buttonclick1 {
Sar V;
V.Skaityti("abc.txt");
}

meta error: [Linker Error] Unresolved external 'Sar::Skaityti(char *)' referenced from C:\DOCUMENTS AND SETTINGS\AURIDAS\DESKTOP\GERAS\UNIT1.OBJ