<分区>
我在编译我的(简单)代码时收到这样的错误消息:
||=== Build: Release in zad12 (compiler: GNU GCC Compiler) ===|
obj/Release/Section.o||In function `MyFigures::Section::Section()':|
Section.cpp|| undefined reference to `vtable for MyFigures::Figure'|
obj/Release/Section.o||In function `MyFigures::Section::Section(Point, Point)':|
Section.cpp|| undefined reference to `vtable for MyFigures::Figure'|
obj/Release/Section.o||In function `MyFigures::Section::~Section()':|
Section.cpp|| undefined reference to `vtable for MyFigures::Figure'|
Section.cpp|| undefined reference to `vtable for MyFigures::Figure'|
obj/Release/Section.o:(.rodata._ZTIN10MyFigures7SectionE[_ZTIN10MyFigures7SectionE]+0x10)||undefined reference to `typeinfo for MyFigures::Figure'|
||=== Build failed: 5 error(s), 0 warning(s) (0 minute(s), 0 second(s)) ===|
还有代码:
#ifndef _FIGURE_H_
#define _FIGURE_H_
namespace MyFigures
{
class Figure
{
public:
Figure(){}
~Figure(){}
virtual void draw();
virtual void move();
virtual void scale(double s);
};
}
#endif
#ifndef _Section_H_
#define _Section_H_
#include "figure.h"
#include "point.h"
#include <exception>
namespace MyFigures
{
class Section : public Figure
{
public:
class badsection : public std::exception
{
public:
const char * what() const throw()
{
return "error";
}
};
Section();
Section(Point start, Point end);
void draw();
void move();
void scale(double s);
~Section();
private:
Point start;
Point end;
};
}
#endif
#include "section.h"
namespace MyFigures
{
Section::Section()
{
}
Section::Section(Point start, Point end)
{
if(start == end)
throw badsection();
}
void Section::draw() {}
void Section::move() {}
void Section::scale(double s) {}
Section::~Section() {}
}
#ifndef _Point_H_
#define _Point_H_
class Point
{
private:
double x,y;
public:
Point();
~Point();
Point(double xx);
Point(double xx, double yy);
Point& operator=(const Point& p);
bool operator==(const Point& p);
};
#endif
#include "point.h"
Point::Point()
{
x = 0;
y = 0;
}
Point::Point(double xx)
{
x = xx;
y = 0;
}
Point::Point(double xx=0, double yy=0)
{
x = xx;
y = yy;
}
Point::~Point()
{
}
Point& Point::operator=(const Point& p)
{
x = p.x;
y = p.y;
return *this;
}
bool Point::operator==(const Point& p)
{
return (x == p.x) && (y == p.y);
}
我试图将 Figure 类中的析构函数设为虚函数，但没有效果(错误仍然存在)。