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从文本文件中读取输入并将其解压缩 – C

运维开发网 https://www.qedev.com 2020-03-02 12:05 出处:网络 作者:运维开发网整理
我正在尝试逐行读取文本文件并将数据提取到我的程序中.本质上,C程序将读取已经采用以下格式的输入文件: Republican Senator John McMahon Democrat Mayor Steven Markel Republican Judge Matt Stevens Democrat Senator Anthony Quizitano S R
我正在尝试逐行读取文本文件并将数据提取到我的程序中.本质上,C程序将读取已经采用以下格式的输入文件:

Republican Senator John McMahon
     Democrat Mayor Steven Markel
     Republican Judge Matt Stevens
     Democrat Senator Anthony Quizitano
     S R
     M D
     J R
     ...
     ..
     ..

格式基本上是前3行包括Party,Position和Name,接下来的行表示“结果”,其形式为:

[第一封信] [党投票]

所以,例如,如果你看到S R,这意味着对参议员投了1票,那就是共和党候选人.

这是我到目前为止所拥有的:

#include<fstream>
            int main()
            {
            std::ifstream input("file.txt");
            }

这是我的理解,这将允许我输入文件,并逐行进行,但我不知道如何从这里开始实现这个…任何帮助?

谢谢!

为了娱乐和荣耀,这是一个基于Boost Spirit的实现.我添加了更多假投票输入,只是因此可能会显示一些内容.

>我不确定候选人和投票之间是否存在1:1的关系(我不是美国公民,我不知道列出的候选人是投票还是投票).所以我决定只使用假数据.

const std::string input = 
    "Republican Senator John McMahon\n"
    "Democrat Senator Anthony Quizitano\n"
    "S R\n"
    "S R\n"
    "S R\n"
    "Democrat Mayor Steven Markel\n"
    "Republican Judge Matt Stevens\n"
    "M D\n"
    "J R\n"
    "S R\n"
    "S R\n";

但是,该代码可用于这两个目的.

>我将输入显示的顺序变得不重要.

>但是,您可以断言,单个字母(S,M,J)实际上对应于该点之前列出的位置.通过使用posletter_check取消注释检查来启用此功能

请参阅http://liveworkspace.org/code/d9e39c19674fbf7b2419ff88a642dc38的现场演示

#define BOOST_SPIRIT_USE_PHOENIX_V3
#define BOOST_RESULT_OF_USE_DECLTYPE
#include <boost/fusion/adapted.hpp>
#include <boost/spirit/include/qi.hpp>
#include <boost/spirit/include/phoenix.hpp>
#include <iomanip>

namespace qi    = boost::spirit::qi;
namespace phx   = boost::phoenix;

struct Candidate { std::string party, position, name; };

BOOST_FUSION_ADAPT_STRUCT(Candidate, (std::string, party)(std::string, position)(std::string, name))

typedef std::map<std::pair<char, char>, size_t> Votes;
typedef std::vector<Candidate> Candidates;

template <typename It>
    struct parser : qi::grammar<It>
{
    mutable Votes _votes;
    mutable Candidates _candidates;

    parser() : parser::base_type(start)
    {
        using namespace qi;
        using phx::bind; using phx::ref; using phx::val;

        start = (line % eol) >> *eol >> eoi;

        line = 
              vote      [ phx::bind(&parser::register_vote, phx::ref(*this), _1) ]
            | candidate [ phx::push_back(phx::ref(_candidates), _1) ]
            ;

        vote %= graph   
                        // Comment the following line to accept any single
                        // letter, even if a matching position wasn't seen
                        // before:
                        [ _pass = phx::bind(&parser::posletter_check, phx::ref(*this), _1) ]  
            >> ' ' 
            >> char_("RD")
            ;

        candidate = (string("Republican") | string("Democrat"))
            >> ' ' 
            >> as_string [ +graph ]
            >> ' ' 
            >> as_string [ +(char_ - eol) ]
            ;
    }

  private:
    bool posletter_check(char posletter) const
    {
        for (auto& c : _candidates)
            if (posletter == c.position[0])
                return true;
        return false;
    }
    void register_vote(Votes::key_type const& key) const
    {
        auto it = _votes.find(key);
        if (_votes.end()==it)
            _votes[key] = 1;
        else
            it->second++;
    }

    qi::rule<It, Votes::key_type()> vote;
    qi::rule<It, Candidate()> candidate;
    qi::rule<It> start, line;
};

int main()
{
    const std::string input = 
        "Republican Senator John McMahon\n"
        "Democrat Senator Anthony Quizitano\n"
        "S R\n"
        "S R\n"
        "S R\n"
        "Democrat Mayor Steven Markel\n"
        "Republican Judge Matt Stevens\n"
        "M D\n"
        "J R\n"
        "S R\n"
        "S R\n";

    std::string::const_iterator f(std::begin(input)), l(std::end(input));

    parser<std::string::const_iterator> p;

    try
    {
        bool ok = qi::parse(f,l,p);
        if (ok)   
        {
            std::cout << "\ncandidate list\n";
            std::cout << "------------------------------------------------\n";
            for (auto& c : p._candidates)
                std::cout << std::setw(20) << c.name << " (" << c.position << " for the " << c.party << "s)\n";

            std::cout << "\nVote distribution:\n";
            std::cout << "------------------------------------------------\n";
            for (auto& v : p._votes)
                std::cout << '(' << v.first.first << "," << v.first.second << "): " << v.second << " votes " << std::string(v.second, '*') << "\n";
        }
        else std::cerr << "parse failed: '" << std::string(f,l) << "'\n";

        if (f!=l) std::cerr << "trailing unparsed: '" << std::string(f,l) << "'\n";
    } catch(const qi::expectation_failure<std::string::const_iterator>& e)
    {
        std::string frag(e.first, e.last);
        std::cerr << e.what() << "'" << frag << "'\n";
    }
}

输出:

candidate list
------------------------------------------------
        John McMahon (Senator for the Republicans)
   Anthony Quizitano (Senator for the Democrats)
       Steven Markel (Mayor for the Democrats)
        Matt Stevens (Judge for the Republicans)

Vote distribution:
------------------------------------------------
(J,R): 1 votes *
(M,D): 1 votes *
(S,R): 5 votes *****
0

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