Reading data from files

I am having trouble getting the code below to work. My first problem is that the first checkSpecials function returns all but the first line.

The second checkSpecials function returns 0 for all values. I dont know if I am using the correct way to assign "names" to the vaules.

the input file looks something like this:

5 2 2 670.60

Code:

---

#include <iostream>
#include <fstream>
#include <cstdlib>
#include <string>
using namespace std;

void checkSpecials(ifstream& infile)
{
        cout << endl << "Display orders stored in file orders.dat: " << endl;
        while (infile)
        {
                string temp;
                getline(infile, temp);
                cout << temp << endl;
        }
}
 
void checkSpecials(ifstream& infile, ofstream& outfile)
{
        int numSpecials = 0;
        float commision = 0;
        int noServed =0;
        float avgSpent = 0;
        int count = 0;
        int value, members, specials, wine, bill, total;

        infile >> members >> specials >> wine >> bill;

        while(infile >> value)
        {
                noServed ++;
                total += total;
                avgSpent = ((total / noServed) + (total % noServed));

                if((members >= 5) && (specials >= 4) && (wine >= 2))
                {
                       
                                        numSpecials ++;
                }
               
        }

        outfile << "Number of families that ordered the special: " << numSpecials << endl
                  << "Commision earned from the special meal: " << commision << endl
                  << "Average spent per person for the evening: " << avgSpent << endl;
        }


int main()
{
        ifstream infile;
        ofstream outfile;
        string outName = "c:\\datafiles\\result.dat";
        string inName = "c:\\datafiles\\orders.dat";

        int members, special, wine;
        float total;

        infile.open(inName.c_str());
        outfile.open(outName.c_str());
        outfile.precision(2);

        if  (!infile)
        {
                cout << "Cannot open infile " << infile << " Aborting!" << endl;
                exit(1);
        }

        if (!outfile)
        {
                cout << "Cannot open oufile " << outfile << " Aborting!." << endl;
                exit(1);
        }

               
        checkSpecials(infile);

        checkSpecials(infile, outfile);

        infile.close();
        outfile.close();
               
        return 0;
}

---

Well to read the file for the second time, you need to
- reset the eof() error state
- rewind to the beginning of the file.

Code:

---

void checkSpecials(ifstream& infile)
{
    cout << endl << "Display orders stored in file orders.dat: " << endl;
    while (infile)
    {
        string temp;
        getline(infile, temp);
        cout << temp << endl;
    }
}

---

This is flawed and suffers from the same issue as using end-of-file testing to control loops. Test the read operation itself:

Code:

---

void checkSpecials(ifstream& infile)
{
    string temp;
    cout << endl << "Display orders stored in file orders.dat: " << endl;
    while (getline(infile, temp))
    {
        cout << temp << endl;
    }
}

---

Brilliant thank you. That solves my first problem.

Would you also be able to help with the second problem? With the input file containing a few lines in the format: 5 2 5 680.00. Am I correct in using

Code:

---

infile >> members >> specials >> wine >> bill;

---

to input the values?

Code:

---

void checkSpecials(ifstream& infile, ofstream& outfile)
{
        int numSpecials = 0;
        float commision = 0;
        int noServed =0;
        float avgSpent = 0;
        int count = 0;
        int value, members, specials, wine, bill, total;

        infile >> members >> specials >> wine >> bill;

        while(infile >> value)
        {
                noServed ++;
                total += total;
                avgSpent = ((total / noServed) + (total % noServed));

                if((members >= 5) && (specials >= 4) && (wine >= 2))
                {
                       
                                        numSpecials ++;
                }
               
        }

        outfile << "Number of families that ordered the special: " << numSpecials << endl
                  << "Commision earned from the special meal: " << commision << endl
                  << "Average spent per person for the evening: " << avgSpent << endl;
        }

---