ex17_17_18.cpp

/***************************************************************************
*  @file       main.cpp
*  @author     Queequeg
*  @date       25  Nov 2014
*  @remark     This code is for the exercises from C++ Primer 5th Edition
*  @note       There are some bugs in gcc(include the latest version 4.9.2)
*              to handle regular expression.To compile this program, please
*			   turn to other compilers such as msvs2013 and clang.
***************************************************************************/
//
// Exercise 17.17
// Update your program so that it finds all the words in an input sequence
// that violiate the "ei" grammar rule.

//
// Exercise 17.18
// Revise your program to ignore words that contain "ei" but are not 
// misspellings, such as "albeit" and "neighbor."

#include <iostream>
using std::cout;
using std::cin;
using std::endl;

#include <string>
using std::string;

#include <regex>
using std::regex;
using std::sregex_iterator;

int main()
{
	string s;
	cout << "Please input a sequence of words:" << endl;
	getline(cin, s);
	cout << endl;
	cout << "Word(s) that violiate the \"ei\" grammar rule:" << endl;
	string pattern("[^c]ei");
	pattern = "[[:alpha:]]*" + pattern + "[[:alpha:]]*";
	regex r(pattern, regex::icase);
	for (sregex_iterator it(s.begin(), s.end(), r), end_it; it != end_it; ++it)
		cout << it->str() << endl;

	return 0;
}