By storing the list of words in the binary tree and counting the total number of words, the binary tree adaptively moves the words with high frequency up to reduce the search time of the binary tree. The following code

/***********************genSplay.h***********************/
#ifndef _GENSPLAY_H_
#define _GENSPLAY_H_

#include <iostream>
using namespace std;

// Tree node
template<class T>
class SplayingNode
{
public:
  T info;
  SplayingNode *left, *right, *parent;  // Node pointer
  SplayingNode(){
    left = right = parent = 0;
  }
  SplayingNode(const T &el, SplayingNode *l = 0,
         SplayingNode *r = 0, SplayingNode *p = 0)
         :info(el), left(l), right(r), parent(p){ }
};
//2 tree
template<class T>
class SplayTree
{
protected:
  SplayingNode<T> *root;
  void rotateR(SplayingNode<T> *);  // Spin to the right
  void rotateL(SplayingNode<T> *);  // Rotate to the left
  void continueRotation(SplayingNode<T> *gr, SplayingNode<T> *par,
             SplayingNode<T> *ch, SplayingNode<T> *desc); // Redefine the parent pointer
  void semisplay(SplayingNode<T> *); // Change the tree structure to move the weight up
  void inorder(SplayingNode<T> *);  // In the sequence traversal
  void virtual visit(SplayingNode<T> *){ } // Virtual functions
public:
  SplayTree(){
    root = 0;
  }
  void inorder(){
    inorder(root);
  }
  T *search(const T &);
  void insert(const T &);
};

template<class T>
void SplayTree<T>::continueRotation(SplayingNode<T> *gr, SplayingNode<T> *par,
    SplayingNode<T> *ch, SplayingNode<T> *desc)
{
  if(gr != 0){
    if(gr->right == ch->parent)
      gr->right = ch;
    else
      gr->left = ch;
  }
  else
    root = ch;
  if(desc != 0)
    desc->parent = par;
  par->parent = ch;
  ch->parent = gr;
}

template<class T>
void SplayTree<T>::rotateR(SplayingNode<T> *p)
{
  p->parent->left = p->right;
  p->right = p->parent;
  continueRotation(p->parent->parent, p->right, p, p->right->left);
}

template<class T>
void SplayTree<T>::rotateL(SplayingNode<T> *p)
{
  p->parent->right = p->left;
  p->left = p->parent;
  continueRotation(p->parent->parent, p->left, p, p->left->right);
}
template<class T>
void SplayTree<T>::semisplay(SplayingNode<T> *p)
{
  while(p != root){
    if(p->parent->parent == NULL){
      if(p->parent->left == p)
        rotateR(p);
      else
        rotateL(p);
    }
    else if(p->parent->left == p){
      if(p->parent->parent->left == p->parent){
        rotateR(p->parent);
        p = p->parent;
      }
      else{
        rotateR(p);
        rotateL(p);
      }
    }
    else{
      if(p->parent->parent->right == p->parent){
        rotateL(p->parent);
        p = p->parent;
      }
      else{
        rotateL(p);
        rotateR(p);
      }
    }
    if(root == NULL)
      root = p;
  }
}

template<class T>
T *SplayTree<T>::search(const T &el)
{
  SplayingNode<T> *p = root;
  while(p != NULL){
    if(p->info == el){
      semisplay(p);
      return &p->info;
    }
    else if(el < p->info)
      p = p->left;
    else
      p = p->right;
  }
  return 0;
}

template<class T>
void SplayTree<T>::insert(const T &el)
{
  SplayingNode<T> *p = root, *prev = NULL, *newNode;
  while(p != 0){
    prev = p;
    if(el < p->info)
      p = p->left;
    else
      p = p->right;
  }
  if((newNode = new SplayingNode<T>(el, 0, 0, prev)) == 0){
    cerr << "no room for new node.\n";
    exit(1);
  }
  if(root == 0)
    root = newNode;
  else if(el < prev->info)
    prev->left = newNode;
  else
    prev->right = newNode;
}

template<class T>
void SplayTree<T>::inorder(SplayingNode<T> *p)
{
  if(p != 0){
    inorder(p->left);
    visit(p);
    inorder(p->right);
  }
}

#endif // _GENSPLAY_H_

/***********************Splay.cpp***********************/
#include <iostream>
#include <fstream>
#include <cctype>
#include <cstring>
#include <cstdlib> //exit(0)
#include "genSplay.h"
using namespace std;

// Class used as a counting object
class Word
{
private:
  char *word;
  int freq;
  friend class WordSplay;
  //friend ostream & operator<<(ostream &out, const Word &wd);
public:
  Word(){
    freq = 1;
  }
  int operator==(const Word &ir) const{
    return strcmp(word, ir.word) == 0;
  }
  int operator<(const Word &ir) const{
    return strcmp(word, ir.word) < 0;
  }
};

class WordSplay : public SplayTree<Word>
{
private:
  int differentWords, wordCnt;
  void visit(SplayingNode<Word> *);
public:
  WordSplay(){
    differentWords = wordCnt = 0;
  }
  void run(ifstream &, char *);
};

void WordSplay::visit(SplayingNode<Word> *p)
{
  differentWords++;
  wordCnt += p->info.freq;
}

void WordSplay::run(ifstream &fin, char *filename)
{
  char ch = ' ', i;
  char s[100];
  Word rec;
  while(!fin.eof()){
    while(1){
      if(!fin.eof() && !isalpha(ch))
        fin.get(ch);
      else
        break;
    }
    if(fin.eof())
      break;
    for(i = 0; !fin.eof() && isalpha(ch); i++){
      s[i] = toupper(ch);
      fin.get(ch);
    }
    s[i] = '\0';
    if(!(rec.word = new char[strlen(s) + 1])){
      cerr << "no room for new words.\n";
      exit(1);
    }
    strcpy(rec.word, s);
    Word *p = search(rec);
    if(p == 0)
      insert(rec);
    else
      p->freq++;
  }
  inorder();
  cout << "\n\nFile " << filename
     << " contains " << wordCnt << " words among which "
     << differentWords << " are different.\n";
}

int main()
{
  char Filename[80];
  WordSplay SplayTree;
  cout << "enter a filename: ";
  cin >> Filename;
  ifstream fin(Filename);
  if(fin.fail()){
    cerr << "cannot open " << Filename << endl;
    return 1;
  }
  SplayTree.run(fin, Filename);
  fin.close();

  return 0;
}

Come back at your leisure to add other functions:

Write the corresponding word and file to the file, first order traversal Optimize performance