Thread: Can someone explain what I'm doing wrong in writing the file?

I'm given a file to read that each line has a name, item, and amount in it such as this..

Jeff,clothes,23
Barry,book,78
Casey,phone,24
Jeff,book,47

Here is my homework site for more detail...
http://omega.uta.edu/~darin/CSE1320/1320-hw05.pdf

But, the approach I have looked at is to read the file line by line and split up the name, item, and number into their own arrays. Then our teacher suggested for each name, create a file of their own with the items and number of items in it.

Then create an array of structures to keep track of the names of the files created.

My code right now doesn't have the structures yet. But I'm trying to append the item and amount to the files I create. What it is doing apparently in this code is writing over the file with the newest item and amount.

For example,

instead of having the file Jeff filled with....
clothes,23
book,47

it just has book,47.

How would I fix this to where it writes in every line?

Code:

int main(void){


    char buffer[50];
    char name[50];
    char item[50];
    int amount[50];
    FILE *fp;
    FILE *fp2;
    char filename[50];


    
    if ( (fp = fopen("names.csv", "r" )) == NULL )
    {
       printf("Couldn't open file\n");
       exit(1); 
    }
    
    while(fgets(buffer, sizeof(buffer), fp))
    {
       sscanf(buffer,"%[^,] ,%[^,], %s", &name, &item, &amount);
       strcat (name, ".txt");


       if( (fp2 = fopen(name, "w")) == NULL )
       {
           printf("unable to open %s\n", filename);
           exit( 1 );
       }
     
       fprintf(fp2, "item is %s, amount is %s\n", &item, &amount);
       fclose(fp2);
     
       fclose(fp);
    }
getchar();
return 0;
}

Ok cool, silly error on my part. That works now. I'll come back if I need anymore help

double post, but I figured I'd use this one instead of starting a new one.

One of the requirements and easiest ways to do this is ...

"You will need to keep track of the names of the files created; for this, create an array of
structures."

My question is how would I do this? I'm guessing I build a structure that just has....

Code:

struct names
{
       char name[15];
};

and then somehow while reading the file, I need to use that structure for each name?

Don't really understand this completely. Thanks for any advice.

In class has your instructor shown how to access members within a structure? Think of a many boxes on a shelf and each box contains listings of names. So you need to be able to open up and view each box, ie box1, box2 and read the contents within those. Hope this analogy was not to confusing or made it worse for you.

Below link may help in regards to c file I/O. The key here is that you need to know how your file is set up to delimit it accordingly to parse out your names and types to assign their respective structure members, perhaps within a loop of sorts.
C File I/O Tutorial - Cprogramming.com

Ok, I just read through that and used the quiz too, will bookmark for more use.

One last question though..

Would you personally say that how I initially grab the file would be the best way for this project? I grab the file, and split it into it's three different parts while reading it and then create a file for each of these names and add there items and amount in there.

I'm leaving out the part where I need to keep track of how many names right now. If this part is right/a good way to go, then I will be able to work on the structure next.

code is right here and works fine as far as creating the files it needs to create.

Code:

int main(void){


    char buffer[50];
    char name[15];
    char item[99];
    int amount;
    FILE *fp;
    FILE *fp2;
    int i;


    
    if ( (fp = fopen("names.csv", "r" )) == NULL )
    {
       printf("Couldn't open file\n");
       exit(1); 
    }
    
    while(fgets(buffer, sizeof(buffer), fp))
    {
       sscanf(buffer,"%[^,] ,%[^,], %d", &name, &item, &amount);
       strcat (name, ".txt");


       //create file for names
       if( (fp2 = fopen(name, "a")) == NULL )
       {
           printf("unable to open %s\n", name);
           exit( 1 );
       } 
       fprintf(fp2, "%s,%d\n", &item, amount);
       fclose(fp2);
     }
     fclose(fp);
}

Ok, I'll continue to work on it.
I want to thank you for all your help though. You helped me understand this a lot more.

Thanks, but I have to confess that I have learned a ton as well from these forums. Trying to help others helps me too!