C++实现文本查询程序

此程序可以用于查询一个英语文本中某个单词出现的次数和显示所在行数

#include<iostream>
#include<istream>
#include<fstream>
#include<ostream>
#include<string>
#include<list>
#include<vector>
#include<array>
#include<deque>
#include<algorithm>
#include<iterator>
#include<map>
#include<utility>
#include<set>
#include<memory>
#include<sstream>
using namespace std;
using namespace placeholders;
using line_no = vector<string>::size_type;
class Queryresult;
class Textquery{
    public:

        Textquery(ifstream&);
        Queryresult query(const string&) const;

    private:
        shared_ptr<vector<string>> file;
        map<string,shared_ptr<set<line_no>>> wm;
    };
Textquery::Textquery(ifstream &is):file(new vector<string>)
{
    string text;
    while(getline(is,text))
    {
        file->push_back(text);
        int n = file->size() - 1;
        istringstream line(text);
        string word;
        while(line >> word)
        {
            auto &lines = wm[word];
            if (!lines)
                lines.reset(new set<line_no>);
            lines->insert(n);
        }
    }
}

class Queryresult{
    friend ostream& print(ostream&, const Queryresult&);
    public:
        Queryresult(string s,shared_ptr<set<line_no>> p, shared_ptr<vector<string>> f):
            sougth(s),lines(p),file(f){}
    private:
        string sougth;
        shared_ptr<set<line_no>> lines;
        shared_ptr<vector<string>> file;

};
Queryresult Textquery::query(const string &sougth) const
{
    static shared_ptr<set<line_no>> nodata(new set<line_no>);
    auto loc = wm.find(sougth);
    if (loc == wm.end())
        return Queryresult(sougth, nodata, file);
    else
        return Queryresult(sougth, loc->second, file);
}

string make_plural(size_t ctr, const string &word, const string &ending)
{
    return (ctr > 1) ? word + ending : word;
}
ostream &print(ostream & os, const Queryresult &qr)
{
    os << qr.sougth << "occurs" << qr.lines->size() << " " << make_plural(qr.lines->size(),"time","s") << endl;
    for(auto num:*qr.lines)
        os << "t(line" << num + 1 << ")" << *(qr.file->begin() + num) << endl;
    return os;
}
void runQueries(ifstream &infile)
{
    Textquery tp(infile);
    while(true)
    {
        cout << "enter word to look for , or q to quit:";
        string s;
        if (!(cin >> s) || s == "q")
            break;
        print(cout,tp.query(s)) << endl;
    }
}
int main()
{
    ifstream infile;
    infile.open("text1.txt");
    runQueries(infile);
    return 0;
}

样例文本

George Osborne is preparing a campaign to
become the next head of the International Monetary Fund. The former chancellor has told
friends that he is considering a bid to replace Christine Lagarde and become the fund’s first British managing
director in Washington. The IMF, jointly governed by 189 countries, was set…

运行结果

最后

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