file input don't know where to start

[tefflox]

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.

[WolfPack]

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.

[tefflox]

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:

project03.cpp: In function ‘int main()’:
project03.cpp:48: error: invalid conversion from ‘int*’ to ‘long int*’
project03.cpp:48: error: initializing argument 2 of ‘bool loadArrays(const char*, long int*, int*, int*, int&, int)’
project03.cpp:49: error: invalid conversion from ‘int*’ to ‘const long int*’
project03.cpp:49: error: initializing argument 2 of ‘void printArrays(std::ostream&, const long int*, const int*, const int*, int)’

I'm using gnu compiler if this matters.. what am i doing wrong? thx

[WolfPack]

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.

[tefflox]

oh, now i see that. thx