# C++ file handling q

**URL:** <https://boards.straightdope.com/t/c-file-handling-q/233021>\
**Category:** Factual Questions\
**Created:** [March 7, 2004, 9:33pm UTC](https://boards.straightdope.com/t/c-file-handling-q/233021 "2004-03-07T21:33:19Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![HPL](https://avatars.discourse-cdn.com/v4/letter/h/3da27b/32.png) [@HPL](https://boards.straightdope.com/u/HPL)\
**Post date:** [March 7, 2004, 9:33pm UTC](https://boards.straightdope.com/t/c-file-handling-q/233021/1 "2004-03-07T21:33:19Z")

</div>

I’m having a hell of a time with a problem and I can’t seem to figure out how to make it work.

I’m building a database program to let users insert, remove, edit and display products. Products are written a .txt file for retrieval just prior to display.

## My problem is, every time I read out, I always get one more entry then I read in and I can’t seem to figure out how to make it stop doing it. OUTPUT:

I made it this farI made it this farI made it this far  
Name: name  
Catagory: catagory  
Description: description  
Store: stores  
Related: related  
Price: 1.00

Name: name2  
Catagory: cat2  
Description: description2  
Store: stores2  
Related: related2  
Price: 2.00

## Name: Catagory: Description: Store: Related: Price: 2.00

void list::read()  
{

//declare variables  
char tempname[50];  
char tempcatagory[15];  
char tempdescription[100];  
char tempstore[50];  
char temprelated[100];  
float tempprice;  
pnum = 0;

//wipe before read in  
for (int i=0; i\<noofprod; ++i)  
{  
plist\*.name[0] = ‘\0’;  
plist\*.catagory[0] = ‘\0’;  
plist\*.description[0] = ‘\0’;  
plist\*.store[0] = ‘\0’;  
plist\*.related[0] = ‘\0’;  
plist\*.price = 0.0;  
}

//open the file  
in.open(“product.txt”);

//checks for file presence  
//If the file doesn’t exist, dump back to the menu  
if(!in)  
cout\<\<“There are no products. Please enter some!”\<\<endl;  
//If the file does exist, continue  
else  
if(in)  
{  
//begin read in loop  
do  
{

```
            //read in name
            in.get(tempname, 50, '

```

');  
in.clear();  
in.get();

```
            //copy to record
            strcpy(plist[pnum].name, tempname);

            //read in catagory
            in.get(tempcatagory, 15, '

```

');  
in.clear();  
in.get();

```
            //copy to record
            strcpy(plist[pnum].catagory, tempcatagory);

            //read in description
            in.get(tempdescription, 100, '

```

');  
in.clear();  
in.get();

```
            //copy to record
            strcpy(plist[pnum].description, tempdescription);

            //read in store
            in.get(tempstore, 50, '

```

');  
in.clear();  
in.get();

```
            //copy to record
            strcpy(plist[pnum].store, tempstore);

            //read in related
            in.get(temprelated, 100, '

```

');  
in.clear();  
in.get();

```
            //copy to record
            strcpy(plist[pnum].related, temprelated);

            //read in price
            in&gt;&gt;tempprice;
            in.clear();
            in.get();

            //copy to record
            plist[pnum].price = tempprice;

            //increment counter
            ++pnum;

            //error checking to make sure the loops are recorded
            cerr&lt;&lt;"I made it this far";
    //end read-in loop
    }
    while(!in.eof());

```

//end if  
}

//close the file  
in.close();

//end function  
}

//Function to display products by name  
void list::display\_order()const  
{

//Begin display loop  
for(int i=0; i\<pnum; ++i)  
{  
//Display members  
cout\<\<"  
Name: "\<\<plist\*.name\<\<endl;  
cout\<\<"Catagory: "\<\<plist\*.catagory\<\<endl;  
cout\<\<"Description: "\<\<plist\*.description\<\<endl;  
cout\<\<"Store: "\<\<plist\*.store\<\<endl;  
cout\<\<"Related: "\<\<plist\*.related\<\<endl;  
cout\<\<"Price: "\<\<plist\*.price\<\<endl;

//End the display loop  
}

//End the display function  
}

## PRODUCT.TXT(my file)

## name catagory description stores related 1 name2 cat2 description2 stores2 related2 2

---

<div class="post-metadata">

**Author:** ![NBIT33](https://avatars.discourse-cdn.com/v4/letter/n/71c47a/32.png) [@NBIT33](https://boards.straightdope.com/u/NBIT33)\
**Post date:** [March 7, 2004, 9:38pm UTC](https://boards.straightdope.com/t/c-file-handling-q/233021/2 "2004-03-07T21:38:13Z")

</div>

> [@HPL](#):
>
> I’m having a hell of a time with a problem and I can’t seem to figure out how to make it work.
> 
> I’m building a database program to let users insert, remove, edit and display products. Products are written a .txt file for retrieval just prior to display.
> 
> My problem is, every time I read out, I always get one more entry then I read in and I can’t seem to figure out how to make it stop doing it.
> 
> \<CODE SNIPPED\>
> 
> ## PRODUCT.TXT(my file)
> 
> ## name catagory description stores related 1 name2 cat2 description2 stores2 related2 2

If your output is running 1 more time than your input, then intuitively I would think you should try running your output loop one less time:

for(int i=0; i\<(pnum-1); ++i)

instead of

for(int i=0; i\<pnum; ++i)

---

<div class="post-metadata">

**Author:** ![erislover](https://avatars.discourse-cdn.com/v4/letter/e/71e660/32.png) [@erislover](https://boards.straightdope.com/u/erislover)\
**Post date:** [March 7, 2004, 9:53pm UTC](https://boards.straightdope.com/t/c-file-handling-q/233021/3 "2004-03-07T21:53:13Z")

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Your read in loop does not count pnum==0 as an entry; the first entry is actually when pnum==1. Your display loop, however, is counting pnum==0 as something to display. You could condition the **for** loop as  
for (;pnum\>0;pnum–)  
to achieve what you want. Though I didn’t test the code.