"Undefined reference to vtable in Line "in constructor

Question

I'm getting the error message stated in the title. I'm trying to construct a class Line which has inherited the class Shape. I get an error in the

Shape(color) {}

execution in the line constructor.

Header files (Shape and Line in one, Color in another)

Shape.h :

#ifndef SHAPE
#define SHAPE

#include "Image.h"
class Shape{
private:
    Color color;
public:
    Shape (const Color & col) : color(col){}
    virtual void Draw(Image & figure) const = 0;

};

class Line : public Shape{
public:
    Line (int x1, int y1, int x2, int y2, const Color & color);
    virtual void Draw(Image & figure) const;

private:
    int x1, y1, x2, y2;
};
#endif // SHAPE

Image.h :

struct Color {
    Color( unsigned char r, unsigned char g, unsigned char b ) 
    : red( r ), green( g ),     blue( b ) {
    }
    Color() : red( 0 ), green( 0 ), blue( 0 ) {
    }
    unsigned char red, green, blue;
};

And here is the Shape.cpp

#include "Shape.h"

Line::Line( int x1, int y1, int x2, int y2, const Color &color )
    : x1( x1 )
    , x2( x2 )
    , y1( y1 )
    , y2( y2 )
    , Shape(color){
}

Maybe add a Color(Color&) constructor to struct Color? – Peter L. Apr 23 '13 at 21:15 — Peter L., Apr 23 '13 at 21:15

score 0 · Answer 1 · answered Apr 23 '13 at 21:19

0

struct Color must be declared prior to being used as a member of Shape.

answered Apr 23 '13 at 21:19

alexrider

4,449
1
17
27

How would one do such a thing? – user1784297 Apr 23 '13 at 21:21
By putting `Color` [above Shape](http://coliru.stacked-crooked.com/view?id=cda018b999e446bb39a1f208ca095ba4-50d9cfc8a1d350e7409e81e87c2653ba) – alexrider Apr 23 '13 at 21:23
But Color is in "Image.h". And "Image.h" is included in "Shape.h". Isn't that sufficient? – user1784297 Apr 23 '13 at 21:25
It is the title : "undefined reference to `vtable for Line'" in , Shape (color) { – user1784297 Apr 23 '13 at 21:29
Looks like Shape.cpp doesn't get compiled/linked with the rest of the code. Check your build log. – alexrider Apr 23 '13 at 21:36
Still hoping for an answer to this one! Been stuck for 2 days :) – user1784297 Apr 25 '13 at 16:14
Can you post you build log with command lines used to build and link? – alexrider Apr 25 '13 at 16:23

score 0 · Answer 2 · answered Apr 25 '13 at 16:29

0

It appears that retracting "void" from the Draw declaration in the Line class worked. For some reason

answered Apr 25 '13 at 16:29

user1784297

103
12

"Undefined reference to vtable in Line "in constructor

2 Answers2