C++ >>和<<的重载出错

在类中重载了<<和>>,但还是提示没有找到,无法使用
代码如下:
#include
#include
#include
using namespace std;

class Student
{
public:
ostream& operator << (ostream & out)
{
out<<"学号:"< return out;
}
istream& operator >> (istream & in)
{
if (&in == &cin)
{
cout<<"从键盘输入"< cout in>>id;
cout<<"请输入姓名:";
in>>name;
cout<<"请输入成绩1:";
in>>score[0];
cout<<"请输入成绩2:";
in>>score[1];
cout<<"请输入成绩3:";
in>>score[2];
cout<<"请输入成绩4:";
in>>score[3];
cout<<"请输入成绩5:";
in>>score[4];
cout<<"请输入成绩6:";
in>>score[5];
cout<<"请输入成绩7:";
in>>score[6];
cout<<"请输入成绩8:";
in>>score[7];
return in;
}
else
{
in>>id>>name;
for (int i = 0; i {
in>>score[i];
}
return in;
}}

private:
string id;
string name;
float score[8];

};

int main()
{
Student s[3];
cin>>s[0];
cin>>s[1];
cin>>s[2];
ofstream out_file("Record.dat",ios::app);
for (int i = 0; i<3;++i)
{
out_file<<s[i]<<endl;
}
return 0;
}

谢谢大神

简单的输入重载示例:
istream& operator>>(istream& in, Student& s)
{
in>>s.no;//输入学生的学号
/*其他操作*/
return in;
}

 你需要重载
ostream & operator<<(ostream &os,const Student &c)

http://blog.csdn.net/jarvischu/article/details/6628559
http://www.cnblogs.com/zhuyf87/archive/2013/02/25/2932441.html