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私が読んでいるファイルには、都市に関するデータが含まれています。必要なデータだけを抽出して、それを都市オブジェクトに適用するにはどうすればよいのでしょうか。以下は私の都市のクラスです。

    #include <iostream>
    #include <string>
    #include <cstdlib>
    #include "City.h"
    using namespace std;

    /*
     * Define the constructor for the class 
     */
    City::City(string city_name, string state, int longitude, int latitude, int population) {
        this->city_name = city_name;
        this->state     = state;
        this->longitude = longitude;
        this->latitude = latitude;
        this->population = population;
    }

    /*
     *Accessors
     */ 
    string City::getCity() { 
                return city_name; 
        }

    string City::getState() { 
            return state; 
        }

    int City::getLongitude() {
            return longitude;
        }

    int City::getLatitude() {
            return latitude;
        }

    int City::getPopulation() {
            return population;
        }

    /*
     * Mutators 
     */ 
    void City::setCity(string city_name) {
            this->city_name = city_name;
        }
    void City::setState(string state) {
            this->state = state;
        }
    void City::setLongitude(int longitude) {
            this->longitude = longitude;
        }
    void City::setLatitude(int latitude) {
            this->latitude = latitude;
        }
    void City::setPopulation(int population) {
            this->population = population;
        }


    /*
     * Sorting methods
     */
    void City::sortByCity() {
            // Code to sort cities by city name
    }

    void City::sortByLongitude() {
            // Code to sort cities by longitude
    }  

これは、ファイルに含まれている、読みたいテキストの種類の例です。

1063061 | OH | Tobias | ppl | Marion | 39 | 101 | 404118N | 0830359W | 40.68833 | -83.06639 ||||| 985 ||| Monnett 1063062 | OH | Todds | ppl | Morgan | 39 | 115 | 393129N | 0815049W | 39.52472 | -81.84694 |||||983|||ストックポート

私の質問は、「|」をどのように除外するかです。私のファイル入力ストリームからの文字?また、必要な文字列のみを抽出するにはどうすればよいですか。(例:city_nameまたは州のOHとしてのTobias)私の都市オブジェクトを作成するため。ありがとうございました

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3 に答える 3

1

行を文字列にロードする必要があります。std :: getline()次に、ある文字列から別の文字列にコピーするwhileループを追加する必要があります。

while(loadedstring!='|')
{
newstring=newstring+loadedstring[i];
i++;
}
于 2013-01-30T19:52:44.033 に答える
1

区切り文字'|'でgetlineを使用します フォーマットされた入力データに適合した入力シーケンスを記述します

ifstream myfile ("input.txt");
string s;
getline (myfile,s,'|')
于 2013-01-30T20:35:04.850 に答える
0

ここであなたにとって良い例のように思われるログファイルパーサーを実装するCSクラスに割り当てがありました。

#ifndef _LOGFILE_PARSE_H_
#define _LOGFILE_PARSE_H_

#include string
#include vector
#include fstream
#include sstream
#include time.h

#include "lphashtable.h"
#include "schashtable.h"

/**
 * LogfileParser class: Provides an interface for querying logfiles of a
 * particular format.
 */
class LogfileParser {
    public:
        /**
         * Constructs a new LogfileParser from the name of a log file.
         *
         * @param fname The name of the log file to open.
         */
        LogfileParser( const std::string & fname );

        /**
         * Determines if a given customer has ever visited the given url.
         *
         * @param customer The customer name.
         * @param url The url.
         * @return A boolean value indicating whether the customer visited
         *  the url.
         */
        bool hasVisited( const std::string & customer, const std::string & url ) const;

        /**
         * Determines *when* a customer last visited a given url. If the
         * customer has not visited the given url, the output of this
         * function should be the default time_t.
         *
         * @param customer The customer name.
         * @param url The url.
         * @return A time_t representing when the customer last visited the
         *  given url.
         */
        time_t dateVisited( const std::string & customer, const std::string & url ) const;

        /**
         * Gets all of the unique urls that have been visited.
         *
         * @return A vector of urls that were visited in the logfile. Note
         *  that **there should be no duplicates in this vector**.
         */
        std::vector< std::string > uniquePages() const;

    private:
        /**
         * LogLine structure: Represents the information contained in a
         * single line of the logfile.
         */
        class LogLine {
            public:
                /**
                 * Constructs a LogLine from a string (actual physical line
                 * in the logfile).
                 *
                 * @param line The line in the file to extract info from.
                 */
                LogLine( const std::string & line );

                std::string customer; /**< The customer for this line, */
                std::string url;      /**< The url for this line. */
                time_t date;          /**< The date for this line. */
        };

        /**
         * HashTable used to determine when a customer visited a given url.
         *
         * Hint: think about what your key should be for this. How could
         * you construct a unique, string key to find information for a
         * given customer and url?
         */
        LPHashTable< std::string, time_t > whenVisitedTable;

        /**
         * Vector containing the unique urls found in the logfile. You
         * should fill this in the constructor.
         *
         * @note This vector **should not contain duplicates!**
         */
        std::vector< std::string > uniqueURLs;

};
#endif

ソースファイル:

#include "logfile_parser.h"
#include iostream

using std::string;
using std::vector;
using std::ifstream;
using std::istringstream;

/**
* Constructs a LogLine from a string (actual physical line in the
* logfile).
*
* @param line The line in the file to extract info from.
*/
LogfileParser::LogLine::LogLine( const string & line ) {
    istringstream iss( line );
    iss >> customer;
    customer = customer.substr(1, customer.length()-3);
    iss >> url;
    string dte = "";
    string dline;
    do {
        iss >> dline;
        dte += dline;
    } while( iss );

    date = time(NULL);
    tm * tme = localtime( &date );
    strptime( dte.c_str(), "%c", tme );
    // force correct DST
    tme->tm_isdst = 1;
    date = mktime( tme );
}

/**
* Constructs a new LogfileParser from the name of a log file.
*
* @param fname The name of the log file to open.
*/
LogfileParser::LogfileParser( const string & fname ) : whenVisitedTable( 256 ) {
    SCHashTable< string, bool > pageVisitedTable( 256 );

    ifstream infile( fname.c_str() );
    string line;
    while( infile.good() ) {
        getline( infile, line );

        // if the line length is 0, move on to the next loop iteration
        if( line.length() == 0 )
            continue;           
        // otherwise parse the line and update the hash tables and vector
        LogLine ll( line );
        string uniqueString =(ll.customer + ll.url);
        if(whenVisitedTable.keyExists(uniqueString))
        {
            if(whenVisitedTable[uniqueString] < ll.date)
            whenVisitedTable[uniqueString] = ll.date;
        }
        else if (!whenVisitedTable.keyExists(uniqueString))
            whenVisitedTable.insert(uniqueString, ll.date);


        if(pageVisitedTable.keyExists(ll.url))
            pageVisitedTable[ll.url] = true;        
        else if (!pageVisitedTable.keyExists(ll.url))
        {
            pageVisitedTable.insert(ll.url, true);      
            uniqueURLs.push_back(ll.url);
        }

        /*
        * Given the LogLine above, you should be able to update the member
        * variable hash table and any other hash tables necessary to solve
        * this problem. This should also build the uniqueURLs member
        * vector as well.
        */
    }
    infile.close();
}

/**
* Determines if a given customer has ever visited the given url.
*
* @param customer The customer name.
* @param url The url.
* @return A boolean value indicating whether the customer visited the url.
*/
bool LogfileParser::hasVisited( const string & customer, const string & url ) const {
    string myString = (customer + url);
    if(whenVisitedTable.keyExists(myString))
        return true;
    else return false;

}

/**
* Determines *when* a customer last visited a given url. If the customer
* has not visited the given url, the output of this function should be the
* default time_t.
*
* @param customer The customer name.
* @param url The url.
* @return A time_t representing when the customer last visited the given
*  url.
*/
time_t LogfileParser::dateVisited( const string & customer, const string & url ) const {
    string myString = (customer + url);
    if(whenVisitedTable.keyExists(myString))
        return whenVisitedTable.find(myString);
    else
        return time_t(); // replaceme
}

/**
* Gets all of the unique urls that have been visited.
*
* @return A vector of urls that were visited in the logfile. Note
*  that **there should be no duplicates in this vector**.
*/
vector<string> LogfileParser::uniquePages() const {
    return uniqueURLs;
}


I removed the <> from the #include statements for some so they showed.  I did not write this whole class, a TA did some of it, and I was responsible for the rest.  There are many more files to this, but this is the class that seems to be most relevant for you.
于 2013-01-30T19:54:43.737 に答える