Write a C program which inputs a file as a command-line arguments and detects whether the file is JPEG(Joint Photographic Experts Group) or not.
Approach:
- We will give an image as a command line argument while executing the code.
- Read the first three bytes of the given image(file).
- After reading the file bytes, compare it with the condition for JPEG file i.e., if the first, second, and third byte of the given file is 0xff, 0xd8, and 0xff respectively then the given file is JPEG file.
- Else it is not a JPEG File.
Below is the implementation of the above approach:
// C program for the above approach #include <ctype.h> #include <stdio.h> #include <string.h> // Driver Code int main( int argc, char * argv[])
{ // If number of command line
// argument is not 2 then return
if (argc != 2) {
return 1;
}
// Take file as argument as an
// input and read the file
FILE * file = fopen (argv[1], "r" );
// If file is NULL return
if (file == NULL) {
return 1;
}
// Array to store the char bytes
unsigned char bytes[3];
// Read the file bytes
fread (bytes, 3, 1, file);
// Condition for JPEG image
// If the given file is a JPEG file
if (bytes[0] == 0xff
&& bytes[1] == 0xd8
&& bytes[1] == 0xff) {
printf ( "This Image is "
"in JPEG format!" );
}
// Else print "No"
else {
printf ( "No" );
}
return 0;
} |