ece282/lab03/append.c

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

int main( int ac , char *av[] )
{

	// print the help flag thing
	if ( (ac < 2 ) || ( ! strcmp (av[1], "--help") ) ) {
		printf ("%s\n", "This program appends a source file to a destination file.");
		printf ("%s\n", "syntax:");
		printf ("\t%s\n", "append DESTINATION SOURCE");
	} else {
		if (ac < 3) {
			printf ("%s\n", "Destination file must be provided.");
			printf ("%s\n", "See 'append --help'.");
			return 1;
		} else {
			// av[1] is destination
			// av[2] is source
			FILE *destination, *source;

			// open the source file
			source = fopen (av[2], "r");

			// error if there is no source
			if ( !source ) {
				printf ("Error: Source file '%s' not found.\n", av[2]);
				return 1;
			}

			// buffer for reading
			char buffer[128];

			// open (or create) the destination file
			destination = fopen (av[1], "a");

			// read into buffer and write to file
			while (fgets (buffer, sizeof (buffer), source)) {
				fprintf (destination, "%s", buffer);
			}

			// clean up
			fclose (source);
			fclose (destination);
		}
	}

	return 0;
}