关于c ++：对’vtable for classname’的未定义引用

undefined reference to 'vtable for classname'

本问题已经有最佳答案，请猛点这里访问。

Possible Duplicate:
Undefined reference to vtable

我有一个学生在档案上-学生。这是它的构造器：

1
2
3
4
5
6
7
8
9
10
11
12

class Student
{
protected:
double _id;
double _salary;
double _grade_average;

public:
Student(double id, double salary,double average):
_id(id),_salary(salary),_grade_average(average)
{}
};

然后我得到错误：

undefined reference to 'vtable for Student'

有什么问题？

这是一个大学.h文件：

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15

#include"Student.h"
class University : public Student
{
public:
virtual double getValue();
University(char university_id,double id, double average,double salary):
_university_id(university_id),Student(id,average,salary)
{
}

private:
char _university_id;
static double how_many;
static double sum_avg_grades;
};