In C, is there a way to get the size of multiple files with names matching a string?

Question

I have files something like this:

file1_a_etc.txt,
file1_b_etc.txt
file2_a_z.txt
file2_b_z.txt

I want to get the size of files with "a" i.e. file2_a_z.txt & file1_a_etc.txt

I have got a large number of files this way, so cant specify each name individually.

I am a beginner at C.
I know how to read the size of a single file. And I am working on windows.

#include <stdio.h>       
#include <sys/stat.h>   // For struct stat and stat()

struct stat attr;
void main()
{   
if(stat("filename.txt", &attr) == 0)
{

    float x;
    x=(attr.st_size)/1048576.0;             //1MB=1048576 bytes
    printf("Filesize: %.2f MB", x);
}
else
{
  // couldn't open the file
    printf("Couldn't get file attributes...");
}
}

score 1 · Accepted Answer · answered Feb 19 '15 at 08:05

1

For Windows console there is function _findfirst. For first parameter put *a*.txt.

answered Feb 19 '15 at 08:05

i486

6,491
4
24
41

is it possible to search all sub-folders for doing the same thing??i.e. searching a file that matches a string.. – itzcutiesush Mar 03 '15 at 07:07

score 0 · Answer 2 · edited May 23 '17 at 12:13

0

You need to iterate over the files in a given directory while searching for the substring in each file name.

This answer, under the section (Unix/Linux), specifies how to iterate over each filename while comparing for an exact match, you can modify the strcmp function call to strstr to look for a substring.

edited May 23 '17 at 12:13

Community

1
1

answered Feb 19 '15 at 08:11

Snehasish Kumar

1
1

score 0 · Answer 3 · answered Feb 19 '15 at 08:13

0

You could make an Array of strings to store all filenames. Then you can use the strchr function to test, if an 'a' or other character is the name. The use of this function is explained e.g at http://www.tutorialspoint.com/ansi_c/c_strchr.htm

answered Feb 19 '15 at 08:13

Kai

103
4

Klas Lindbäck · Answer 4 · 2015-02-19T08:22:47.997

Reading directories programmatically can be done with readdir.

You could do something like this:

#include <dirent.h>
#include <errno.h>
#include <stdio.h>
#include <string.h>

static void lookup(const char *dir)
{
    DIR *dirp;
    struct dirent *dp;


    if ((dirp = opendir(dir)) == NULL) {
        perror("couldn't open '.'");
        return;
    }


    do {
        errno = 0;
        if ((dp = readdir(dirp)) != NULL) {
            if (strstr(dp->d_name, "_a_") == NULL)
                continue;


            (void) printf("found %s\n", dp->d_name);
            // Add code to handle the file
        }
    } while (dp != NULL);


    if (errno != 0)
        perror("error reading directory");
    (void) closedir(dirp);
    return;
}

readdir is part of POSIX.1-2001, which is supported by unix/linux-type systems (including OS/X) but only some windows compilers. If you are programming in windows you may have to use another solution.

In C, is there a way to get the size of multiple files with names matching a string?

4 Answers4