Programs won't write to a file, and I do not know if it is reading it

Question

This program is supposed to read files and write them. I took the file open checks out because they kept causing errors. The problem is that the files open like they are supposed to and the names are correct but nothing is on any of the text screens. Do you know what is wrong?

#include<iostream>
#include<fstream>
#include<cstdlib>
#include<iomanip>
using namespace std;
int main()
{
    ifstream in_stream; // reads itemlist.txt
    ofstream out_stream1; // writes in items.txt
    ifstream in_stream2; // reads pricelist.txt
    ofstream out_stream3;// writes in plist.txt
    ifstream in_stream4;// read recipt.txt
    ofstream out_stream5;// write display.txt

    float price='  ',curr_total=0.0;
    int itemnum='  ', wrong=0;
    char next;

    in_stream.open("ITEMLIST.txt", ios::in); // list of avaliable items
    out_stream1.open("listWititems.txt", ios::out); // list of avaliable items           
    in_stream2.open("PRICELIST.txt", ios::in);           
    out_stream3.open("listWitdollars.txt", ios::out);               
    in_stream4.open("display.txt", ios::in);    
    out_stream5.open("showitems.txt", ios::out);

  in_stream.close(); // closing files.
  out_stream1.close();
  in_stream2.close();
  out_stream3.close();
  in_stream4.close();
  out_stream5.close();
  system("pause");

    in_stream.setf(ios::fixed);
    while(in_stream.eof())
    {
        in_stream >> itemnum;
        cin.clear();
        cin >> next;
    }

    out_stream1.setf(ios::fixed);
    while (out_stream1.eof())
    {
        out_stream1 << itemnum;
        cin.clear();
        cin >> next;
    }

    in_stream2.setf(ios::fixed);
    in_stream2.setf(ios::showpoint);
    in_stream2.precision(2);
    while((price== (price*1.00)) && (itemnum == (itemnum*1)))
         {
             while (in_stream2 >> itemnum >> price) // gets itemnum and price
             {
                 while (in_stream2.eof())  // reads file to end of file
                 {
                 in_stream2 >> itemnum;
                in_stream2 >> price;
                price++;
                curr_total= price++;
                in_stream2 >> curr_total;
                cin.clear();  // allows more reading
                cin >> next;
                }

            }
        }

    out_stream3.setf(ios::fixed);
    out_stream3.setf(ios::showpoint);
    out_stream3.precision(2);
    while((price== (price*1.00)) && (itemnum == (itemnum*1)))
        {
         while (out_stream3 << itemnum << price)
             {
                 while (out_stream3.eof())  // reads file to end of file
                 {
                 out_stream3 << itemnum;
                 out_stream3 << price;
                 price++;
                 curr_total= price++;
                 out_stream3 << curr_total;
                 cin.clear();  // allows more reading
                 cin >> next;
                 }
                return itemnum, price;
            }
        }

    in_stream4.setf(ios::fixed);
    in_stream4.setf(ios::showpoint);
    in_stream4.precision(2);
    while ( in_stream4.eof())
    {
        in_stream4 >> itemnum >> price >> curr_total;
        cin.clear();
        cin >> next;
    }

    out_stream5.setf(ios::fixed);
    out_stream5.setf(ios::showpoint);
    out_stream5.precision(2);
    out_stream5 <<setw(5)<< " itemnum " <<setw(5)<<" price "<<setw(5)<<" curr_total " <<endl; // sends items and prices to receipt.txt 
    out_stream5 << setw(5) <<  itemnum << setw(5) <<price << setw(5)<< curr_total; // sends items and prices to receipt.txt 
    out_stream5 << " You have a total of " << wrong++ << " errors " << endl; 


}

Answer 1

for instance: why are you closing your in_stream before reading it ?

while(in_stream.eof()) should be while(in_stream.good()) or while(!in_stream.eof()), assuming that you'd kept file opened

Answer 2

You should put the file open checks back in and add code which will detect these error conditions and give you descriptive messages about what is wrong. Then when you get those messages you should research those conditions in order to find out how to correct them.

I don't know the proper way for reporting those error conditions in C++, but here is how I used to do it in C:

FILE *infile = fopen(filename, "r");
if (infile == NULL)
{
  perror(filename);
  exit(1);
}

This gives nice error messages like: thisfile: No such file or directory

The exit() call also means that your code exits at the first error. This prevents your program from going on to do damage with invalid assumptions (suppose you accidentally opened the wrong file, and didn't realize it? or accidentally read a bunch of null values because your file wasn't open, and you didn't know?) Often resolving the first error encountered will resolve later errors as well, or at least make them resolvable.

I had to look up the manpage for fopen() to see what it returns in the event of an error to learn that I should do the if (infile == NULL) check. You will have to read the documentation for what you are using.

perror() works by checking the externally defined errno variable. Other C programmers skip perror() and check errno themselves; perror() is simply a convenience method. C++ may have some other, better convenience method. (Without perror(), I would again need to carefully read the fopen() manpage to see that an error causes errno to be set and what the possible values are.)

Perl has an even more convenient means of handling this, which I always liked:

open my $infile, $filename or die "Can't open $filename: $!";

The $! magic variable basically corresponds to the output of the perror() function. And again, internally it's just C code checking errno.

Answer 3

so i have broke this code down and i believe the area i should look at is the

while((price== (price*1.00)) && (itemnum == (itemnum*1)))

code that is causing the problem does anyone agree? so now i need to figure out away to tell the difference bw itemnum and price so i can tally them up to get the total of each at the end? I have to make it so it can read any number and any price.

Answer 4

its a problem with the ifstreams but i dont know how to fix them do anyone know how too??