pex14_6.cpp

数据结构C++代码,经典代码,受益多多,希望大家多多支持

#include <iostream.h>
#include <fstream.h>
#include <stdlib.h>
#include <ctype.h>
#pragma hdrstop

#include "hash.h"
#include "strclass.h"

// extract a word beginning with a letter and possibly
// other letters/digits
int GetWord (ifstream& fin, char w[])
{
   	 char c;
   	 int  i = 0;

    	// skip non-alphabetic input
    	while ( fin.get(c) && !isalpha(c));
        
   	 // return 0 on end of file
    	if (fin.eof())
       	 return 0;
    
   	 // record 1st letter of the word    
    	w[i++] = c;
    
    	// collect letters and digits. NULL terminate
    	while (fin.get(c) && (isalpha(c) || isdigit(c)))
       	 w[i++] = c;
   	 w[i] = '\0';
    
   	 return  1;
}

// function for use by the Hash class
unsigned long hash(String s)
{
   unsigned long hashval = 0;

   // shift hashval left three bits and add in next character
   for(int i=0;i< s.Length();i++)
      hashval = (hashval << 3) + s[i];
   return hashval;
}

// translate each uppercase character of s
// to lower case
void Lowercase(String& s)
{
	for(int i=0;i < s.Length();i++)
		if (isupper(s[i]))
			s[i] = tolower(s[i]);
}

void main(void)
{
	// hash table for words
	HashTable<String> HT(1001,hash);
	// used to initialize hash table and read document
	ifstream fin;
	char s[50];
	String str;
	int misspelled = 0;

	// open "words"
	fin.open("words", ios::in | ios::nocreate);
	if (!fin)
	{
		cerr << "Cannot open \"words\"" << endl;
		exit(1);
	}
	
	// insert each word from the file "words" into the
	// hash table. this is the database containing
	// "correctly spelled" words
	while(fin >> str)
		HT.Insert(str);
	fin.close();
	
	// open the document
	cout << "Enter the name of the document: ";
	cin >> s;
	fin.open(s, ios::in | ios::nocreate);
	if (!fin)
	{
		cerr << "Cannot open " << s << endl;
		exit(1);
	}

	// read through the document and check spelling
	while(GetWord(fin,s))
	{
		// str is String object having value of C++ string s
		str = s;
		// convert str to lowercase
		Lowercase(str);
		// look str up the the hash table
		if (!HT.Find(str))
		{
			// output misspelled word message once
			if (misspelled == 0)
			{
				cout << endl << "Misspelled words:" << endl << endl;
				misspelled = 1;
			}
			// output original word s
			cout << s << endl;
		}
	}
}

/*
<Run>

<File "pex14_6.dat">

She and her friend went
to school.

<Run>

Enter the name of the document: pex14_6.dat

Misspelled words:

went
*/