The following task concerns data that came from a pollution monitoring station with twenty-four instruments monitoring twenty-four aspects of pollution in the air. Periodically a record is added to the file, each record being a line of 49 fields separated by white-space, which can be one or more space or tab characters.

The fields (from the left) are:

 DATESTAMP [ VALUEn FLAGn ] * 24

i.e. a datestamp followed by twenty-four repetitions of a floating-point instrument value and that instrument's associated integer flag. Flag values are >= 1 if the instrument is working and < 1 if there is some problem with it, in which case that instrument's value should be ignored.

A sample from the full data file readings.txt, which is also used in the Text processing/1 task, follows:

Data is no longer available at that link. Zipped mirror available here

1991-03-30	10.000	1	10.000	1	10.000	1	10.000	1	10.000	1	10.000	1	10.000	1	10.000	1	10.000	1	10.000	1	10.000	1	10.000	1	10.000	1	10.000	1	10.000	1	10.000	1	10.000	1	10.000	1	10.000	1	10.000	1	10.000	1	10.000	1	10.000	1	10.000	1
1991-03-31	10.000	1	10.000	1	10.000	1	10.000	1	10.000	1	10.000	1	10.000	1	20.000	1	20.000	1	20.000	1	35.000	1	50.000	1	60.000	1	40.000	1	30.000	1	30.000	1	30.000	1	25.000	1	20.000	1	20.000	1	20.000	1	20.000	1	20.000	1	35.000	1
1991-03-31	40.000	1	0.000	-2	0.000	-2	0.000	-2	0.000	-2	0.000	-2	0.000	-2	0.000	-2	0.000	-2	0.000	-2	0.000	-2	0.000	-2	0.000	-2	0.000	-2	0.000	-2	0.000	-2	0.000	-2	0.000	-2	0.000	-2	0.000	-2	0.000	-2	0.000	-2	0.000	-2	0.000	-2
1991-04-01	0.000	-2	13.000	1	16.000	1	21.000	1	24.000	1	22.000	1	20.000	1	18.000	1	29.000	1	44.000	1	50.000	1	43.000	1	38.000	1	27.000	1	27.000	1	24.000	1	23.000	1	18.000	1	12.000	1	13.000	1	14.000	1	15.000	1	13.000	1	10.000	1
1991-04-02	8.000	1	9.000	1	11.000	1	12.000	1	12.000	1	12.000	1	27.000	1	26.000	1	27.000	1	33.000	1	32.000	1	31.000	1	29.000	1	31.000	1	25.000	1	25.000	1	24.000	1	21.000	1	17.000	1	14.000	1	15.000	1	12.000	1	12.000	1	10.000	1
1991-04-03	10.000	1	9.000	1	10.000	1	10.000	1	9.000	1	10.000	1	15.000	1	24.000	1	28.000	1	24.000	1	18.000	1	14.000	1	12.000	1	13.000	1	14.000	1	15.000	1	14.000	1	15.000	1	13.000	1	13.000	1	13.000	1	12.000	1	10.000	1	10.000	1

Task

 Confirm the general field format of the file.
 Identify any DATESTAMPs that are duplicated.
 Report the number of records that have good readings for all instruments.


#include <boost/regex.hpp>
#include <fstream>
#include <iostream>
#include <vector>
#include <string>
#include <set>
#include <cstdlib>
#include <algorithm>
using namespace std ;
 
boost::regex e ( "\\s+" ) ; 
 
int main( int argc , char *argv[ ] ) { 
   ifstream infile( argv[ 1 ] ) ; 
   vector<string> duplicates ;
   set<string> datestamps ; //for the datestamps
   if ( ! infile.is_open( ) ) { 
      cerr << "Can't open file " << argv[ 1 ] << '\n' ;
      return 1 ; 
   }   
   int all_ok = 0  ;//all_ok for lines in the given pattern e
   int pattern_ok = 0 ; //overall field pattern of record is ok
   while ( infile ) { 
      string eingabe ;
      getline( infile , eingabe ) ;
      boost::sregex_token_iterator i ( eingabe.begin( ), eingabe.end( ) , e , -1 ), j  ;//we tokenize on empty fields
      vector<string> fields( i, j ) ;
      if ( fields.size( ) == 49 ) //we expect 49 fields in a record
         pattern_ok++ ;
      else
         cout << "Format not ok!\n" ;
      if ( datestamps.insert( fields[ 0 ] ).second ) { //not duplicated
         int howoften = ( fields.size( ) - 1 ) / 2 ;//number of measurement
                                                    //devices and values
         for ( int n = 1 ; atoi( fields[ 2 * n ].c_str( ) ) >= 1 ; n++ ) {
            if ( n == howoften ) {
               all_ok++ ;
               break ;
            }
         }
      }
      else {
         duplicates.push_back( fields[ 0 ] ) ;//first field holds datestamp
      }
   }
   infile.close( ) ;
   cout << "The following " << duplicates.size() << " datestamps were duplicated:\n" ;
   copy( duplicates.begin( ) , duplicates.end( ) ,
         ostream_iterator<string>( cout , "\n" ) ) ;
   cout << all_ok << " records were complete and ok!\n" ;
   return 0 ;
}