Frost wrote:
Christopher Benson-Manica wrote:
Frost <ra*******@dgipro.com> wrote:
I am a newbie i have written a c program on unix for line by line
comparison for two files now could some one help on how i could do word
by word comparison in case both lines have the same words but in
jumbled order they should match and print only the dissimilar lines.The
program also checks for multiple entries of the same line.
Here file 2 converts to file 3 which is in the format of file1 and i
compare file1 with file3.
this program right now is checking line by line and for multiple
entries of the same line,and prints only dissimilar lines please can u give me a program which i can check word my word so that if the lines contain the same words but in different positions they should match.
I could, but I will not. At least not directly.
Let us first clean up your program. Then we will discuss what to do
to make it more efficient. The extension of what we do line by line
can be used for the word by word version.
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#define MAX 10000
main( int argc, char *argv[] )
main returns int. Do not rely on implicit int as
C99 made it illegal.
Write
int main (int argc, char **argv)
or
int main (void)
instead.
{
FILE *fp1, *fp2, *fp3;
void filecomp( FILE *, FILE * );
void fileconv( FILE *, FILE * );
This can bite you later on if you move the functionality
out of main(), especially if you rely on implicit int elsewhere
and do not turn up the warning level of your compiler...
if( argc != 4 ) {
fprintf( stderr, "need two files\n" );
exit( 1 );
Non-portable argument to exit(): Use EXIT_FAILURE instead.
To signal success, use EXIT_SUCCESS or 0.
}
fp3=fopen( argv[3], "w" );
fp2=fopen( argv[2], "r" );
if( fp2 == NULL ) {
printf( "cannot open file2\n" );
exit( 1 );
}
if( fp3 == NULL ) {
printf( "cannot open file3\n" );
exit( 1 );
}
fileconv( fp2, fp3 );
fclose( fp2 );
fclose( fp3 );
fp1=fopen( argv[1], "r" );
if( fp1 == NULL ) {
printf( "cannot open file1\n" );
exit( 1 );
}
fp3=fopen( argv[3], "r" );
if( fp3 == NULL ) {
printf("cannot open file3\n");
exit( 1 );
}
Instead of closing and reopening, just open fp3 as "w+"
and rewind() it.
filecomp( fp1, fp3 );
fclose( fp1 );
fclose( fp3 );
exit( 0 );
Matter of taste:
return 0;
does not do exactly the same thing, but is appropriate
as well.}
void fileconv( FILE *fp2, FILE *fp3 )
{
char c;
The return type of fgetc() is int.
EOF is a negative int value.
char may be an unsigned type.
Moreover, fgetc() returns the character value converted
to unsigned char or EOF.
In short:
Make c an int.
while( (c=fgetc(fp2)) != EOF ) {
Note: The macro getc() does the same but may be implemented
more efficiently.
if( c == '.' ) {
c='/';
fputc(c,fp3);
}
else
fputc( c, fp3 );
}
}
void filecomp( FILE *fp1, FILE *fp3 )
{
char line1[MAX], line2[MAX];
char *s1, *s2;
int ctr, octr, a=0, b=1;
int i,count1=0, count2=1, count3=0, count4=0;
Look at these names and tell me you will know what they mean
in twelve months' time. Keep a straight face.
while( ((s1=fgets(line1,MAX,fp1)) != NULL) ) {
count1++;
while( (s2=fgets(line2,MAX,fp3)) != NULL ) {
i=strcmp( s1, s2 );
if( i == 0 ) {
count3++;
}
count2++;
}
if( count3==0 )
printf("line %d of file1 does not match lines of file3\n", count1 );
count2=1;
count3=0;
fseek( fp3, 0, SEEK_SET );
}
if( (s2=fgets(line2,MAX,fp3)) != NULL )
printf( "both files have ended\n" );
}
What is wrong with your approach: You ignore the possibility
that your line length might exceed MAX. Unfortunately, there
is no nice standard C way to do it right but you can use the
public domain ggets()/fggets() of C.B. Falconer which is portable.
How can that make problems?
Suppose l1 is too long and can be decomposed into l1a and l1b;
If we now have the fragments l1a and l1b somewhere in the second
file, we could be lead to the conclusion that the files are
identical even if they are not.
In addition, you will not find lines which are only in the
second file but not in the first one.
Let us consider a line by line comparison without multiple lines
and the points I raised above:
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
/* Use the PD fggets() from
http://cbfalconer.home.att.net/download/ */
#include "ggets/ggets.h"
void fileconv (FILE *conv_src, FILE *conv_dest);
void filecomp (FILE *comp_src, FILE *conv_dest);
int main (int argc, char **argv)
{
FILE *comp_src, *conv_src, *conv_dest;
if (argc != 4) {
fprintf(stderr, "Need THREE files (comp_src conv_src conv_dest)\n");
exit(EXIT_FAILURE);
}
/* Conversion */
conv_dest = fopen(argv[3], "w+");
conv_src = fopen(argv[2], "r");
if (!conv_src || !conv_dest) {
fprintf(stderr, "Cannot open files for conversion\n" );
(void)fclose(conv_dest);
(void)fclose(conv_src);
exit(EXIT_FAILURE);
}
fileconv(conv_src, conv_dest);
(void)fclose(conv_src);
/* Comparison */
comp_src = fopen(argv[1], "r");
if (comp_src == NULL) {
fprintf(stderr, "Cannot open %s\n", argv[1]);
exit(EXIT_FAILURE);
}
rewind(conv_dest);
filecomp(comp_src, conv_dest);
(void)fclose(comp_src);
(void)fclose(conv_dest);
return 0;
}
void fileconv (FILE *conv_src, FILE *conv_dest)
{
int c;
while ((c = getc(conv_src)) != EOF) {
if (c == '.') {
c = '/';
}
if (EOF == putc(c, conv_dest )) {
/* Handle error and return */
}
}
}
void filecomp (FILE *src1, FILE *src2)
{
char *line1, *line2;
size_t line_count = 0;
rewind(src1); /* Does not hurt but makes sure that */
rewind(src2); /* we start from the beginning. */
while (0 == fggets(&line1, src1)) {
int is_equal=0;
++line_count;
if (0 == fggets(&line2, src2)) {
if (!strcmp(line1, line2))
is_equal = 1;
}
else
break;
free(line1); /* Drawback of *ggets(): You have to free() */
free(line2); /* yourself. */
if (!is_equal)
printf("line %lu of comp_src does not match "
"normalized lines of conv_src\n",
(unsigned long)line_count);
}
if (EOF == fggets(&line1, src1)
&& EOF == fggets(&line2, src2))
printf("both files have ended\n");
free(line1);
free(line2);
}
Now, how can we give that at least the functionality you had?
As I understand, you cared nothing about the position of the
lines within the files.
So: Read in all lines of src1, store them in an array a1 of
strings; do the same for src2 (->array a2).
Sort them, e.g. using strcmp() and qsort().
If you are not interested in multiples, you can throw them
out at sorting if you sort yourself or do it after sorting.
Otherwise, go to the last of the multiple lines when
going through the lines.
In the following, I pretend there are no multiple lines:
Now, proceed through the arrays and check all lines whether
they are identical.
BTW: You do not even to generate a separate converted file;
when reading in the lines, do your "conversion" on the fly.
What have we lost? The line numbers. Okay, let us use arrays
a1, a2 of struct line { size_t line_no; char *line_content;}
instead and pass the difference.
Now, the last step: Before sorting the lines, sort every line's
words. This can be, for example, done by splitting the line into
an array of strings where every string is a word, sorting this
array, and generating a string from it containing all the words,
separated by a space.
Just try it; the clc crowd will help you if you struggle with
the details.
Cheers
Michael
--
E-Mail: Mine is an /at/ gmx /dot/ de address.
