Where do these point? (Hint: nowhere in particular.)
OK, here is the 2nd version:
/* K&R2, section 7.7, exercise 7.6
*
* write a program to compare 2 files, printing that first line
* where they differ.
*
* version 1.1
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
enum MAXSIZE { ARRSIZE=1000 };
void compare_files( FILE*, FILE* );
void print_line( const char* );
int main( int argc, char* argv[] )
{
FILE *pf1, *pf2;
if( argc !=3 )
{
fprintf( stderr, "You iDiOT, I expect 2 files as input. \n" );
exit(EXIT_FAILURE);
}
/* open files */
pf1 = fopen( *++argv, "r" );
pf2 = fopen( *++argv, "r" );
/* error check */
if( pf1 == NULL || pf2 == NULL )
{
fprintf( stderr, "error opening files\n");
exit(EXIT_FAILURE);
}
else
{
compare_files( pf1,pf2 );
}
/* don't forget to close the files */
fclose( pf1 );
fclose( pf2 );
return 0;
}
/* compare 2 files */
void compare_files( FILE* pf1, FILE* pf2 )
{
int match;
char c1, c2;
char line1[ARRSIZE];
char line2[ARRSIZE];
char *begin_line1, *begin_line2, *p1, *p2;
match = 1;
while( (fgets( line1, ARRSIZE, pf1 ) != NULL) ||
(fgets( line2, ARRSIZE, pf2 ) != NULL))
{
begin_line1 = line1;
begin_line2 = line2;
p1 = line1;
p2 = line2;
for( c1 = *p1, c2 = *p2; c1 != '\0' && c2 != '\0'; ++p1, ++p2 )
{
if ( c1 != c2 )
{
match = 0;
print_line( begin_line1 );
printf("\n-----------------------\n"); print_line( begin_line2
); }
}
}
}
void print_line( const char* line )
{
while( *line != '\0')
{
puts(*line++);
}
}
================ OUTPUT =======================
[arnuld@raj C]$ gcc -ansi -pedantic -Wall -Wextra 7-6.c
7-6.c: In function `print_line':
7-6.c:96: warning: passing arg 1 of `puts' makes pointer from integer
without a cast
, If one line ends before ther