querymain.cpp

C++Primer 第四版 包括windows 平台下各章的例子程序

/*
 * This file contains code from "C++ Primer, Fourth Edition", by Stanley B.
 * Lippman, Jose Lajoie, and Barbara E. Moo, and is covered under the
 * copyright and warranty notices given in that book:
 * 
 * "Copyright (c) 2005 by Objectwrite, Inc., Jose Lajoie, and Barbara E. Moo."
 * 
 * 
 * "The authors and publisher have taken care in the preparation of this book,
 * but make no expressed or implied warranty of any kind and assume no
 * responsibility for errors or omissions. No liability is assumed for
 * incidental or consequential damages in connection with or arising out of the
 * use of the information or programs contained herein."
 * 
 * Permission is granted for this code to be used for educational purposes in
 * association with the book, given proper citation if and when posted or
 * reproduced.Any commercial use of this code requires the explicit written
 * permission of the publisher, Addison-Wesley Professional, a division of
 * Pearson Education, Inc. Send your request for permission, stating clearly
 * what code you would like to use, and in what specific way, to the following
 * address: 
 * 
 * 	Pearson Education, Inc.
 * 	Rights and Contracts Department
 * 	75 Arlington Street, Suite 300
 * 	Boston, MA 02216
 * 	Fax: [phone]
*/ 

#include "TextQuery.h"
#include <string>
#include <vector>
#include <map>
#include <set>
#include <iostream>
#include <fstream>
#include <cctype>
#include <cstring>
#include <cstdlib>

using std::set;
using std::string;
using std::map;
using std::vector;
using std::cerr;
using std::cout;
using std::cin;
using std::ifstream;
using std::endl;

string make_plural(size_t, const string&, const string&);
ifstream& open_file(ifstream&, const string&);
void print_results(const set<TextQuery::line_no>& locs, 
                   const string& sought, const TextQuery &file)
{
    // if the word was found, then print count and all occurrences
    typedef set<TextQuery::line_no> line_nums; 
    line_nums::size_type size = locs.size();
    cout << "\n" << sought << " occurs "
         << size << " "
         << make_plural(size, "time", "s") << endl;

    // print each line in which the word appeared
    line_nums::const_iterator it = locs.begin();
    for ( ; it != locs.end(); ++it) {
        cout << "\t(line "
             // don't confound user with text lines starting at 0
             << (*it) + 1 << ") "
             << file.text_line(*it) << endl;
    }
}

// program takes single argument specifying the file to query
int main(int argc, char **argv)
{
    // open the file from which user will query words
    ifstream infile;
    if (argc < 2 || !open_file(infile, argv[1])) {
        cerr << "No input file!" << endl;
        return EXIT_FAILURE;
    }

    TextQuery tq;
    tq.read_file(infile);  // builds query map

    // iterate with the user: prompt for a word to find and print results
    // loop indefinitely; the loop exit is inside the while
    while (true) {
        cout << "enter word to look for, or q to quit: ";
        string s;
        cin >> s;

        // stop if hit eof on input or a 'q' is entered
        if (!cin || s == "q") break;

        // get the set of line numbers on which this word appears
        set<TextQuery::line_no> locs = tq.run_query(s);

        // print count and all occurrences, if any
        print_results(locs, s, tq);
     }
    return 0;
}