File input truncation

**Evandb** · 06-01-2004

OK, I am creating a program that will load a text file of CDs into a prgram and add them to a structure. The text file will look like this:
(Each block of three is 1 CD)

Rating1
Title1
Artist1

Rating2
Title2
Artist2
...

Is there some way I can use fscanf to find the number of CDs, because right now it loads my CDs, and all the other garbage data around them. If I could find the number of Cds, I could put that in variable VAR in my program and all would be fine and dandy. Any ideas?

Code:

int loadFile (CD list[])
  {
    FILE *fp;
    char name[50];
    int i;
    int n;

    printf("Enter file name: ");
    scanf("%s",name);
    fp=fopen(name,"r");

        for (i = 0; i < 100; i++) {
        fscanf(fp,"%d\n",&list[i].rating);
        getLine(list[i].title,50,fp);
        getLine(list[i].artist,50,fp);

        }
        n=i;
    fclose(fp);
    return n;
  }

Thanks in advance,
Evan

**MrWizard** · 06-01-2004

Well, you can just keep adding them to a linked list if you want. Otherwise one idea would be to iterate through the file incrementing a counter as each CD is found and then allocating enough room to hold them and re-iterating through the file filling out information.

**Evandb** · 06-01-2004

Well, I dont know what a linked list is.....
and the second option seems viable I guess. Supposedly you can use fscanf to easily get the number of cds, however. Could I find the number of integers in the text then use that as the number of CDs?

**MrWizard** · 06-01-2004

How are you going to get those integers? You'd have to go through the whole file. Maybe you should just put the number of CD's at the top of the file. Then you could parse the first line and you would immediately know.

**Evandb** · 06-01-2004

Going through the whole file isnt a problem, they are going to be small. I cant really change the format of the inputted files though. Any ideas on how to get the integers?

Evan

**MrWizard** · 06-01-2004

Well you said they are formatted like:

Rating1
Title1
Artist1

So I don't know what data type Rating1 is but I would guess an integer or floating-point number. I assume the others are simple strings. If you aren't worried about erroneous formatting you could just keep reading the chunks until you reach the end of the file, incrementing some counter by one each record you read.

**Evandb** · 06-01-2004

Basically all I need is to figure out how many lines I need to input.
Once I get that, I know how far down I need to go.

**Salem** · 06-01-2004

The problem is your for loop, which loops 100 times regardless of any errors your code may generate

Assuming that the file is well-structured, then this should help

Code:

    i = 0;
    while ( i < 100 && fscanf(fp,"%d\n",&list[i].rating) == 1 ) {
        getLine(list[i].title,50,fp);
        getLine(list[i].artist,50,fp);
        i++;
    }

The loop will exit when the array is full, or when there is no more data to be read

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