Question

Open a file handle to each file, use lseek to determine the file's size in bytes and print out the file's size in bytes next to its name. Include a main that does this below.

Please do the above code using C Language.

Answer 1

Solution:

• Look for comments in code to understand it line-by-line.
• Change the name of the file according to your own need.

Code:

#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>

int main()
{
    // Store filename in fn, change it according to your file name
    char fn[10] = "z.jpg";
    int fd;

    // Try to open file, thorw error if file not opened
    if( (fd = open(fn, O_RDONLY) ) < 0 ){
        perror( "open failed" );
        exit( EXIT_FAILURE );
    }

    // Calculate file size in bytes
    off_t  size = lseek(fd, 0, SEEK_END);

    // Print result
    printf("Size of file %s is %ld bytes", fn, size);

    // close file
    close(fd);

    return 0;
}

Output:

Size of file z.jpg is 20145 bytes

Screenshot of code to understand about indentation in code:

PS: Let me know if you have any doubt.