/* fileio-2.c  demonstrates:

	fread(), fwrite()
	array declaration and initilaization

*/

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

int main( int argc, char *argv[] )
{
 	FILE *infile, *outfile;
 	int x=7;
 	unsigned int i;
	short h= 35;
	char c = 'Z';
	int arr1[] = {3,5,7,11,13};
	int arr2[5];

	if (argc < 2 )
	{
		printf("must enter a name for binary output file on cmd line\n");
		exit( EXIT_FAILURE );
	}

 	outfile = fopen(argv[1], "wb" ); /* "wb" means we are writing binary to the file */
 	if (outfile==NULL) /* then the open must have failed */
 	{
		printf("Can't open %s for output.\n", argv[1] );
 		exit( EXIT_FAILURE );
	}

	/* WRITE BINARY DATA TO THE FILE USING fwrite() */

	printf("\nWriting to file %s\n", argv[1] );

	fwrite( &x, sizeof(x), 1, outfile );
	fwrite( &h, sizeof(h), 1, outfile );
	fwrite( &c, sizeof(c), 1, outfile );
	fwrite( arr1, sizeof(arr1), 1, outfile );

	printf("...wrote %d %d %c ",x,h,c);

	for (i=0 ; i< sizeof(arr1)/sizeof(int) ; ++i)
		printf("%d ", arr1[i] );
	printf("\n");

	fclose( outfile );

	/*RE-OPEN THAT FILE AS INPUT AND READ DATA BACK IN AND ECHO TO STDOUT */

 	infile = fopen(argv[1], "rb" ); /* "rb" means we are reading the binary file */
 	if (infile==NULL) /* we really don't expect this to happen considering we just wrote it - but we always test */
 	{
		printf("Can't open %s for input.\n", argv[1] );
 		exit( EXIT_FAILURE );
	}

	printf("\nNow reading from file %s\n", argv[1] );
	x=0; h=0; c=0;

	fread( &x, sizeof(x), 1, infile );
	fread( &h, sizeof(h), 1, infile );
	fread( &c, sizeof(c), 1, infile );
	fread( arr2, sizeof(arr2), 1, infile );

	fclose( infile );

	printf("...read  %d %d %c ",x,h,c);
	for (i=0 ; i< sizeof(arr1)/sizeof(int) ; ++i)
		printf("%d ", arr2[i] );
	printf("\n");


    return 0;
}