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C ++ file input looping thru sets of data

Posted on 2003-03-27
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Last Modified: 2010-04-17
This is my first posting. I need to process the contents of a file that has about 4000
records where every 12 to 36 lines represent a discrete set of data that needs
to be fed into an object.

I have been able to open the file, fill an object but moving to the next
block of 12 to 36 lines has me scratching my head. How do I set up a loop
to do this.

If the “dealer” or “part number” changes then the block of data is done and the next object should be filled.
 Implementation ( .cpp) , the data file itself appear below and the class (.h).


#pragma warning(disable:4786)

#include <iostream>
#include <string>
#include <fstream>
#include <vector>
#include <sstream>
#include <stdlib.h>
#include "partNo.h"


using namespace std;
      

int main()
{

      string s1, s3, s4, s5, s6;  // s1 dealer code, s3 partnumber
      char delim[]=",";  // comma delimter to look for
      
      
      int m = 0;  // index for moving thru vector
      
      ifstream f("test.txt");  // open file
      vector<string> vs;            // vector to hold each string
      vector<string>::iterator strit ;
            
      
      while(f)
            {
                  string s;
                  getline(f,s);
                  vs.push_back(s);  // put the entire string in the vector
            };  



      while(strit != vs.end()) // loop thru the vector parsing each line
      {      
            PartNumber p;                  // part number class

            string s2 = vs[m];  // using vector index assign string to string variable
                        
      
      int j = 0, k =0;  // placement variables
      int i=0;   // for moving thru string
      int dcnt = 0; // count delimters to parse out dealer info
      
      do{
            
            i = s2.find_first_of(delim, j);  // find first delimiter , set i to end of string
            dcnt = dcnt + 1;  // increment delimiter count

            
            // each delimiter parses out a field based on dcnt
            switch(dcnt)
            {
                  case 1 :
                        s3.assign(s2,j,i-j); // assign s2 with k start and i end of string , grab dealer
                  //      cout << s3 << " " ;
                        p.setDealer(s3);   // update dealer in part object
                         break;   // causes exit from loop

                  case 2 :
                        s4.assign(s2,j,i-j);  // grab partnumber
                        p.setPartNumber(s4);  // update partnumber in part object
                        //  cout << s4 << " "  ;
                         break;

                  case 3 :
                        // s5.assign(s2,j,i-j); // date  unused field
                        //      p.set
                        // cout << s5 << " " ;
                        break;

                  case 4 :
                        s6.assign(s2,j,10);   // units
                        //cout << s6 << endl;
                        // convert the string to double
                         p.setDmd(atof(s6.c_str()));  // update dmd vector in part object
                        break;
            }
      
                  j = i+1;  // move the start for delim search forward
      

            //       }while(i < s2.length());    // VERIFY THIS
             }while( i < s2.find_last_of(delim, 0));  // and i >= 0 ???

                  
            p.getDmd();  // prints the units of demand contents of vector      
                        

            m++;   // increment counter for vector
      }
      
      // code needs to be added to put each object into a container for future work

       return 0;
}

/* test.txt note should stop at change
in dealer or partnumber.

  A025,5-280X,01-JAN-03,1.00
A025,5-280X,01-FEB-03,2.00
A025,5-280X,01-MAR-03,3.00
A025,5-280X,01-APR-03,4.00
A025,5-280X,01-MAY-03,5.00
A025,5-280X,01-JUN-03,6.00
A025,5-280X,01-JUL-03,7.00
A025,5-280X,01-AUG-03,8.00
A025,M10130,01-JAN-03,9.00
A082,LE1000,01-JAN-03,10.00
A082,LE1000,01-FEB-03,12.00
A082,LE1000,01-MAR-03,12.00

*/
/// class /////
#include <iostream>

#include <string>


using namespace std;

class PartNumber
{

      public :
            friend ostream& operator<< (ostream& ostr, const PartNumber& obj);

            setDealer( string&  s) ;  // address constants here and below
            setPartNumber(string& s);
            string getDealer() ;
            void getPartNumber();
            setDmd(const double& units);
            void getDmd();
            
            

      private :
            string strDealer;
            string strPartNumber;
            
            double unitDemand;
            vector<double> vdmd;  // hold units of demand
            vector<double>::iterator p ;

};


void PartNumber::getDmd()
{
    if(!vdmd.empty())
      {
            p = vdmd.begin();
            while(p != vdmd.end())
            {
                  cout << *p << "    " << "units stored in obj's vector" << endl ;
                  p++;
            }      
      }
      
}

// set the unitDemand variable
PartNumber::setDmd(const double& units)
{
    vdmd.push_back(units);
}

// set dealer code
PartNumber::setDealer(string& s)
{
      strDealer = s;
}

// set dealer code
PartNumber::setPartNumber(string& s)
{
      strDealer = s;
}


// get the dealer code
string PartNumber::getDealer()
{
      return strDealer;
}

// output the object
ostream& operator<< (ostream& ostr, const PartNumber& obj)   // output
{
      ostr << obj;
      return ostr;
}
0
Comment
Question by:marcon33
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4 Comments
 
LVL 84

Expert Comment

by:ozo
ID: 8222632

strit = vs.begin();
while(++strit != vs.end()) // loop thru the vector parsing each line
     {    
0
 

Author Comment

by:marcon33
ID: 8225485
thanks for the thought. I can process each string held by the vector and even move thru each element of the vector. It is how to stop and start over with a new object that is the problem.
My latest thought is maybe a queue (?) could be used at the beginning , popping the strings that all have the same dealer code and part , then stopping and starting over when they change.
0
 

Accepted Solution

by:
reid_henderson earned 1000 total points
ID: 8226549
If I understand the problem correctly, you want to create a new object if either of the first two numbers change(dealer or part number)

I would create the following variables outside of the main while loop:

vector<PartNumber*> vp; //vector of part numbers
PartNumber* pn = new PartNumber();
vp.push_back(vp); // initialize the first element of vp
int pObjIndex = 0; //keep track of position in vp (unnecessary, but simple)
in your case statements, only do the string assign, i.e.
 case 1 :
   s3.assign(s2,j,i-j);
   //p.setDealer(s3);
   break;

then after the case statement, test for a change in part or dealer:

   if(s3 != (vp[pObjIndex].getDealer()) || s4 != (vp[pObjIndex].getPartNumber())) {
      //create new partnumber object
      PartNumber* pn = new PartNumber();
      //push it onto the vector
      vp.push_back(pn);
      //increment index - this is not a necessary step
      ++pObjIndex;
   }

//now put your information into the top object in vp
vp[pObjIndex]->setDealer(s3);
vp[pObjIndex]->setPartNumber(s4);
vp[pObjIndex]->setDMD(s6);

//I might also suggest more useful names for your strings
//such as currDealerStr - s# is a pain to maintain
//Instead of using pObjIndex you could pop_back the last
//element from vObjIndex or use an iterator for vp.end()-//1;

Ok - I hope I answered the right question... :)
0
 

Author Comment

by:marcon33
ID: 8226925
That gives me plenty to go on. Great clarity. Thanks!
0

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