//函數(shù)聲明部分friend ostream& operator<<<>(ostream&,SinglyList<T>&);    //輸出單鏈表所有元素//函數(shù)定義template <class T>ostream& operator<<<>(ostream &out,SinglyList<T> &list){  out<<"(";  for(Node<T> *next=list.head->next; next != NULL; next = next->next)    {      out<<next->data;      if(next->next != NULL)    out<<",";    }  out<<")\n";  return out;}g++ 編譯時報錯：SinglyList.h:64:55: 錯誤：模板標識符‘operator<< <>’出現(xiàn)在基本模板的聲明中 ostream& operator<<<>(ostream &out,SinglyList<T> &list)SinglyList.h:20:19: 錯誤：‘std::ostream& operator<<(std::ostream&, SinglyList<Computer>&)’的模板標識符‘operator<< <>’不匹配任何模板聲明   friend ostream& operator<<<>(ostream&,SinglyList<T>&);    //輸出單鏈表所有元素 這是我在書上看到的代碼，在我的環(huán)境中編譯報錯。首先對于“operator<<<>”這部分中的<>不明白代表什么意思？先謝了。