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tuple类型的单词查询例子
17.3 重写前面的TextQuery程序,使用tuple代替QueryResult类。
TextQuery.h
#ifndef TEXTQUERY_H#define TEXTQUERY_H#include<iostream>#include<string>#include<fstream>#include<vector>#include<memory>#include<map>#include<set>#include<new>#include<tuple>#include"DebugDelete.h"using namespace std;class QueryResult;class TextQuery{public: using line_no=vector<string>::size_type; TextQuery(ifstream&); tuple<string,shared_ptr<set<TextQuery::line_no>>,shared_ptr<vector<string>>> query(const string&) const; ~TextQuery() { //DebugDelete()(new vector<string>); cout<<"destructing...."<<endl; }private: shared_ptr<vector<string>> file; map<string,shared_ptr<set<line_no>>> wm;};#endif // TEXTQUERY_H
TextQuery.cpp
#include"TextQuery.h"#include<tuple>#include<sstream>TextQuery::TextQuery(ifstream& is):file(new vector<string>,DebugDelete()){ string text; while(getline(is,text)) { file->push_back(text); int n=file->size()-1; string word; istringstream line(text); while(line>>word) { auto &lines=wm[word]; if(!lines) lines.reset(new set<line_no>); lines->insert(n); } }}tuple<string,shared_ptr<set<TextQuery::line_no>>,shared_ptr<vector<string>>>TextQuery::query(const string& sought) const{ static shared_ptr<set<line_no>> nodata(new set<line_no>); auto loc=wm.find(sought); if(loc!=wm.end()) return make_tuple(sought,loc->second,file); else return make_tuple(sought,nodata,file);}
main.cpp
/* * This file contains code from "C++ Primer, Fifth Edition", by Stanley B. * Lippman, Josee Lajoie, and Barbara E. Moo, and is covered under the * copyright and warranty notices given in that book: * * "Copyright (c) 2013 by Objectwrite, Inc., Josee 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 Permissions Department * One Lake Street * Upper Saddle River, NJ 07458 * Fax: (201) 236-3290*/#include <string>using std::string;#include <fstream>using std::ifstream;#include <iostream>using std::cin; using std::cout; using std::cerr;using std::endl;#include <cstdlib> // for EXIT_FAILURE#include "TextQuery.h"#include<tuple>ostream &print(ostream &os,const tuple<string,shared_ptr<set<TextQuery::line_no>>,shared_ptr<vector<string>>> &qr){ os<<get<0>(qr)<<" occurs "<<get<1>(qr)->size()<<" times "<<endl; for(auto num:*get<1>(qr)) os<<"\t(line "<<num+1<<" ) " <<(*get<2>(qr))[num]<<endl; return os;}void runQueries(ifstream &infile){ // infile is an ifstream that is the file we want to query TextQuery tq(infile); // store the file and build the query map // iterate with the user: prompt for a word to find and print results while (true) { cout << "enter word to look for, or q to quit: "; string s; // stop if we hit end-of-file on the input or if a ‘q‘ is entered if (!(cin >> s) || s == "q") break; // run the query and print the results print(cout, tq.query(s)) << endl; }}// program takes single argument specifying the file to queryint main(int argc, char **argv){ // open the file from which user will query words ifstream infile; // open returns void, so we use the comma operator XREF(commaOp) // to check the state of infile after the open if (argc < 2 || !(infile.open(argv[1]), infile)) { cerr << "No input file!" << endl; return EXIT_FAILURE; } runQueries(infile); return 0;}
DebugDelete.h
#include<iostream>#include<new>using namespace std;class DebugDelete{public: DebugDelete(ostream &s=cerr):os(s) {} template <typename T> void operator()(T *p) const { os<<"deleting shared_ptr "<<endl; delete p; }private: ostream &os;};
tuple类型的单词查询例子
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