file input don't know where to start
 

Hello, this is my first post here. I'm taking c++ as an elective course, and I'm doing great until now. The problem I'm having is taking data from a txt file formatted line by line #### # ## for product id, store number, and quantity. I'm supposed to read this data and store it in three different arrays for each token. I think I can get it from there, but I don't know where to start, which library to use, confused by existing tutorials I've read, getting frustrated. Plz help.

Re: file input don't know where to start
 

You don't need anything complex. You will only have to use the <string>, <fstream> and <iostream> libraries. You will have to read some file input tutorials in C++. Even that is not that complex.

Re: file input don't know where to start
 

some progress made. i may have just needed the personal note --have been working on this stuff all day, the end of the term is coming on fast and we just took test 1 of 3 yesterday. here she is:

#include <iostream>

#include <fstream>

#include <string>

using namespace std;





bool  loadArrays(const char fileName[], long idArray[], 

        int  storeArray[], int qtyArray[], int & count, int maxCells);



void printArrays(ostream & where, const long idArray[], 

           const int storeArray[], const int qtArray[], int  count);



bool extractData(const char newFileName[],int requestId, int baseQty,

          const long idArray[], const  int storeArray[],

                const int qtArray[], int  count, int & newcount);



const int ORDER_VALUE = 500;



int main() {





/*

fileName          - the Windows name of the file created in step 1

newFileName         - the Windows file name of the file of extracted records



requestId         - the product id number used to extract data

   ORDER_VALUE  - the quantity value used to extract data, make this

                     a global constant with a value of 500        



        idArray         - the array of id numbers

        storeArray         - the array of store numbers

        qtyArray         - the array of quantities



        count                 - the actual number of cells filled in the arrays

        newcount         - the number of extracted records written to 



*/

        char fileName[]         = "products.txt";

        char newFileName[]  = "list.txt"; 



        int requestID;

        int idArray[ORDER_VALUE], storeArray[ORDER_VALUE], qtyArray[ORDER_VALUE];

        int count = 0, newCount = 0;

        



        if( loadArrays(fileName, idArray, storeArray, qtyArray, count, 20) )

                printArrays(cout, idArray, storeArray, qtyArray, count);



        return 0;



} // end main







bool  loadArrays(const char fileName[],long idArray[], 

                                int  storeArray[], int qtyArray[], int & count, int maxCells) {

        

        ifstream in;

        in.open(fileName);



        if(!in) return false;



        for(int i = 0; !in.eof(); i++) {

                in >> idArray[i];

                in >> storeArray[i];

                in >> qtyArray[i];

                count = i;

        }

        in.close();



        return true;

}



void printArrays(ostream & where, const long idArray[], 

                const int  storeArray[], const int qtyArray[], int count) {



        for(int i = 0; i <= count; i++) 

                where << idArray[i] << " " << storeArray[i] << " " << qtyArray[i] << endl;





}



bool extractData(const char newFileName[],int requestId, int baseQty,

                       const long idArray[], const  int storeArray[],

                                   const int qtArray[], int  count, int & newcount) {





}

which gives the following errors:
I'm using gnu compiler if this matters.. what am i doing wrong? thx

Re: file input don't know where to start
 

That is because you have declared the second arguments of loadArray and printArray as a long array but you are inputing an int array.

Change the declaration of idArray from int to long, or just use int in the function declarations. I dont think you will want it to use long arrays. The range of int should be enough.

Re: file input don't know where to start
 

oh, now i see that. thx