详解C++编程中的虚函数

{ cout<<"num:"<<num<<"nname:"<<name<<"nscore:"<<score<<"nn";

} //声明公用派生类Graduate

class Graduate:public Student {

public: Graduate(int, string, float, float);//声明构造函数

void display( );//声明输出函数 private:float pay;

}; // Graduate类成员函数的实现

void Graduate::display( )//定义输出函数 {

cout<<"num:"<<num<<"nname:"<<name<<"nscore:"<<score<<"npay="<<pay<<endl; }

Graduate::Graduate(int n, string nam,float s,float p):Student(n,nam,s),pay(p){} //主函数

int main() {

Student stud1(1001,"Li",87.5);//定义Student类对象stud1 Graduate grad1(2001,"Wang",98.5,563.5);//定义Graduate类对象grad1

Student *pt=&stud1;//定义指向基类对象的指针变量pt pt->display( );

pt=&grad1; pt->display( );

return 0; }

运行结果如下：

num:1001(stud1的数据) name:Li
score:87.5
num:2001 (grad1中基类部分的数据) name:wang
score:98.5