&怎么用的
程序代码：#include"iostream.h"
class cstudent
{
public:
friend ostream& operator<<(ostream& os,cstudent stu);
friend istream& operator>>(istream& is,cstudent& stu);
private:
char strname[10];
char strid[10];
int fscore[3];
};
ostream& operator<<(ostream &os,cstudent stu)
{
os<<endl<<"请输入学生信息："<<endl<<"姓名"<<stu.strname<<endl<<"学号"<<stu.strid<<endl;
os<<"三门成绩为："<<stu.fscore[0]<<"\t"<<stu.fscore[1]<<"\t"<<stu.fscore[2]<<endl;
return os;
}
istream& operator>>(istream& is,cstudent& stu)
{
cout<<"请输入学生信息："<<endl<<"姓名";
is>>stu.strname;
cout<<"学号：";
is>>stu.strid;
cout<<"三门成绩";
is>>stu.fscore[0]>>stu.fscore[1]>>stu.fscore[2];
return is;
}
void main()
{
cstudent one ;
cin>>one;
cout<<one;
}
friend ostream& operator<<(ostream& os,cstudent stu);
friend istream& operator>>(istream& is,cstudent& stu);这两个定义为什么不一样 ，多了个& ，还有这里面的所有&的位置到底是怎么放的 怎么书上有放在左 放在右 ，但是我换个位置 编译没错误 运行就不行啊
