C++ 模板类的实例化

在尝试实例化模板化类的数据成员时，我经常遇到以下错误：

Proj3Aux.h:28: error: ISO C++ forbids declaration of ‘AugmentedBinarySearchTree’ with no type
Proj3Aux.h:28: error: expected ‘;’ before ‘<’ token

BinaryNode类的定义在该给定代码之上，在ABS cpp文件中，所有方法都以正确的方式定义：

template <class Comparable>
<return type> AugmentedBinarySearchTree<Comparable>::<method>(<parameters>)

---

看起来像是名称查找问题。您确定模板类AugmentedBinarySearchTree是在Proj3Aux之前声明的吗？在Proj3Aux.h中，是否包含声明AugmentedBinarySearchTree的标头？@DanielStrul是的，它们位于单独的文件中，@crayzeewulf AugmentedBinarySearchTree.h包含在文件中。它们可能位于单独的文件中，但包含的顺序错误。特别是，为什么在头文件的末尾有一行代码写着include AugmentedBinarySearchTree.cpp？？？@DanielStrul我也不明白，但是我们不应该编辑讲师提供的ABS代码。

template <class Comparable>
class AugmentedBinarySearchTree
{
 public:
  /*------------Constructors/Destructors-------------*/

  explicit AugmentedBinarySearchTree();
  AugmentedBinarySearchTree(const AugmentedBinarySearchTree<Comparable> & rhs);
  ~AugmentedBinarySearchTree();


  /*--------------Facilitators------------------------*/

  int remove(const Comparable & x);
  bool IsPerfect();
  // bool IsComplete(); <-- Extra Credit!
  void PrintLevels(int numlevels);
  void makeEmpty();

  /*---------------Getters---------------------------*/

  int RemoveResidue(); /* Assume RemoveResidue will always be called after Prin\
t */
  const Comparable & NthElement(int n);
  int Rank(const Comparable & x);
  const Comparable & Median();
  BinaryNode<Comparable> * findMin(BinaryNode<Comparable> *t) const;


  /*---------------Setters---------------------------*/

  int insert(const Comparable & x);

 private:

  int insert(const Comparable & x, BinaryNode<Comparable> * & t) const;
  int remove(const Comparable & x, BinaryNode<Comparable> * & t) const;
  void PrintLevels(queue <BinaryNode<Comparable> *> q, int levels);
  void RemoveResidue(BinaryNode<Comparable> * & t, int *deletions) const;
  BinaryNode<Comparable> * NthElement(BinaryNode<Comparable> *t, int *nodesVisi\
ted, int n) const;
  void Rank(const Comparable & x, BinaryNode<Comparable> *t, int *nodesVisited)\
 const;
  bool IsPerfect(queue <BinaryNode<Comparable> *> q, int height);
  void makeEmpty(BinaryNode<Comparable> * & t) const;
  //IsComplete  <-- Extra Credit!

  /*------------------Members-----------------------------*/
  BinarySearchTree<Comparable> m_tree;
  BinaryNode<Comparable> *root;
};

#include "AugmentedBinarySearchTree.cpp"

template <class Comparable>
<return type> AugmentedBinarySearchTree<Comparable>::<method>(<parameters>)

#ifndef PROJ3_AUX_H_
#define PROJ3_AUX_H_

#include <iostream>
#include <string>
#include <fstream>
#include "AugmentedBinarySearchTree.h"
using namespace std;

const char COMMENT = '#';

class Proj3Aux
{

 private:
  //AugmentedBinarySearchTree<int> m_tree;
  string m_currentCmd;
  vector<int> m_inputs;

 public:
  /*
   * Enum to contain all commands available
   */
  enum COMMANDS {PRINT, RESIDUALS, RANK, NTH, MEDIAN, REMOVE, PERFECT,
                 COMPLETE};

  /*
   * Proj3Aux
   * Default class constructor
   * Preconditoins: none
   * Postconditions: new instance of Proj3Aux is created
   */
  Proj3Aux();