allword3.cc  From Astrachan pp 386-389
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#include <iostream.h>
#include <fstream.h>
#include <stdlib.h>                // for exit
#include "CPstring.h"
#include "vector.h"
#include "prompt.h"
#include "ctimer.h"

// author: Owen Astrachan
//
// lists all words in an input file, but avoids duplicates
// uses class WordList to encapsulate behavior
//
// 5-15-95

class WordList
{
  public:
    WordList(int size);             // constructor,  specify size of list
    void Update(const string & word);   // update occurrences of word
    int GetUnique();                // return # of unique words in list
    int GetTotal();                 // return # of total words in list
    void Print();                   // print all words in list
  private:

    int myCount;                    // # of entries stored in myList
    int mySize;                     // capacity of myList
    int myTotal;                    // # of words (non-unique)
    Vector<string> myList;          // storage for strings
    
    int Search(const string & key); // returns index in myList of key
};

WordList::WordList(int size)
   : myCount(0),
     mySize(size),
     myTotal(0),
     myList(size)
{
    // all work done in initializer list
}

int WordList::Search(const string & key)
// postcondition: returns index at which key occurs in myList
//                returns -1 if key does not occur     
{
    int k;
    for(k=0; k < myCount; k++)
    {
        if (myList[k] == key)     // found key in list
        {
            return k;
        }
    }
    return -1;
}

void WordList::Update(const string & word)
// postcondition: updates occurrence of word
//                adds word to list if not already present
//                increments count of total # of words     
{
    int loc = Search(word);

    myTotal++;
    
    if (loc == -1)                 // not already in list
    {
        if (myCount >= mySize)
        {
            mySize *= 2;
            myList.SetSize(mySize);
        }
        myList[myCount] = word;
        myCount++;
    }
}

void WordList::Print()
// postcondition: all elements of myList printed
{
    int k;
    for(k=0; k < myCount; k++)
    {
        cout << myList[k] << endl;
    }
    cout << endl << "# of words = " << myCount << endl;
}

int WordList::GetUnique()
// postcondition: returns # unique words in list     
{
    return myCount;
}

int WordList::GetTotal()
// postcondition: returns total # of words in list
//                same as # of times Update called     
{
    return myTotal;
}

int main()
{
    string word;                       // word read from file
    string filename = PromptString("enter name of file: ");
    ifstream input;
    WordList wlist(5000);
    CTimer timer;
    
    input.open(filename);
    if (input.fail())
    {
        cout << "could not open file " << filename << endl;
        exit(0);
    }
    
    while (input >> word)              // reading word succeeded
    {
        timer.Start();
        wlist.Update(word.Downcase());
        timer.Stop();
    }
    wlist.Print();

    cout << "total words (non-unique): " << wlist.GetTotal() << endl;
    cout << "total time for update = " << timer.CumulativeTime() << endl;
    return 0;
}

Sample output:

allword3
enter name of file: honor
duke
university
undergraduate
honor
code
its
...
engineering
when
observe
committed
violation
this
code.

# of words = 112
total words (non-unique): 192
total time for update = 0.03