c++ a missing vtable error

Question

I am getting a really weird error related to missing vtable for a given class constructor and destructor. Please help me to resolve this.

Undefined symbols for archi

Answer 1

Found it,,trying with the sample, here is an exmaple.

class Shape{

public:
virtual int areas();
virtual void display();

virtual ~Shape(){};
};

The compiler complained

Undefined symbols for architecture x86_64:
"typeinfo for Shape", referenced from:
  typeinfo for trian in main_file.o
 "vtable for Shape", referenced from:
  Shape::Shape() in main_file.o
  NOTE: a missing vtable usually means the first non-inline virtual member      function has no definition.
   ld: symbol(s) not found for architecture x86_64
  clang: error: linker command failed with exit code 1 (use -v to see invocation)
  make: *** [cpp_tries] Error 1enter code here

The modification is empty or any inline content inside {} next to the virtual function

class Shape{

public:
    virtual int areas(){};
    virtual void display(){};

    virtual ~Shape(){};
};

Basically, its not finding the function definition for the non-inline virtual functions.