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//Download by http://www.NewXing.com /* * 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: (617) 848-7047 */ #include "Query.h" #include "TextQuery.h" #include <set> #include <algorithm> #include <iostream> using std::set; using std::ostream; using std::inserter; using std::set_difference; using std::set_union; using std::set_intersection; // returns lines not in its operand's result sets set<TextQuery::line_no> NotQuery::eval(const TextQuery& file) const { // virtual call through the Query handle to eval set<TextQuery::line_no> has_val = query.eval(file); set<line_no> ret_lines; // for each line the input file, check whether that line is in has_val // if not, add that line number to ret_lines for (TextQuery::line_no n = 0; n != file.size(); ++n) if (has_val.find(n) == has_val.end()) ret_lines.insert(n); return ret_lines; } // returns intersection of its operands' result sets set<TextQuery::line_no> AndQuery::eval(const TextQuery& file) const { // virtual calls through the Query handle to get result sets for the operands set<line_no> left = lhs.eval(file), right = rhs.eval(file); set<line_no> ret_lines; // destination to hold results // writes intersection of two ranges to a destination iterator // destination iterator in this call adds elements to ret set_intersection(left.begin(), left.end(), right.begin(), right.end(), inserter(ret_lines, ret_lines.begin())); return ret_lines; } // returns union of its operands' result sets set<TextQuery::line_no> OrQuery::eval(const TextQuery& file) const { // virtual calls through the Query handle to get result sets for the operands set<line_no> left = lhs.eval(file), right = rhs.eval(file); // destination to hold results, start by copying lines from left set<line_no> ret_lines(left); // inserts the lines from right that aren't already in ret_lines ret_lines.insert(right.begin(), right.end()); return ret_lines; }