Determining file size

I have a (hopefully) quick question. I have been searching around on the internet and through some books but can't seem to find an answer.

I am using text files to store matrices where the elements are separated by tabs (on each line). What I want to do is figure out the number of columns and rows in these files. I figure I could run a routine to count the number of lines to the bottom of the file as well as have another counter that increases by 1 after each fscanf until fscanf reaches \n. This seems pretty slow and cumbersome - is there a faster way?

I am a applied math grad student and am taking a HPC course next semester so I am learning C over break since I don't have much CSCI experience. Any critiques on this code? I know there aren't any things to catch exceptions and check input but other than that stuff what do you guys think? Thanks a lot in advance

Code:

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#include <stdio.h>

FILE *f1;

int main (int argc, const char * argv[]) {
        char inputname[50];
        int matnum1, exit;
       
        exit = 0;
       
        printf("Input filename (must be less than 50 characters including the extension: ");
        scanf("%s", inputname);
        printf("Opening file %s\n",inputname);
       
        f1 = fopen(inputname, "r");
        while (exit != 1) {
                fscanf(f1, "%d\t",&matnum1);
                printf("%d\n",matnum1);
                if (feof(f1)) {
                        exit = 1;
                }
        }
       
   
    return 0;
}

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8 views and no comments? Is the question not clear or do you guys not know the answer?

In case you are working on Linux, and all you need is to "figure out the number of columns and rows in these files", here's a quick command-line solution using awk:
To get the no. of rows:
awk 'END { print NR }' YourFileName
To get the no. of columns:
awk 'END { print NF }' YourFileName

Note 1: There will definitely be better solutions!
Note 2: Assuming all rows have same no. of elements. Column count will depend on the no. of elements in last row.

SourceForge.net: Scanf woes - cpwiki
Unfortunately, there is no function to get rows or columns directly from a file in C. You would have to read a line and read the number of tabs there is in the line to figure out the number of columns. And read all lines to figure out number of rows.

A better solution would instead be to keep track of number of rows and columns and write them to the file, say at the first 8 bytes or so.

Use the stat() function to get file info such as it's size...

Quote:

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Originally Posted by Elysia

SourceForge.net: Scanf woes - cpwiki
Unfortunately, there is no function to get rows or columns directly from a file in C. You would have to read a line and read the number of tabs there is in the line to figure out the number of columns. And read all lines to figure out number of rows.

A better solution would instead be to keep track of number of rows and columns and write them to the file, say at the first 8 bytes or so.

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Good idea - that's what I will do.