"c_beginner" <sa***********@REMOVETHISgmail.com>
wrote in message
news:44***********************@news.sunsite.dk...
Dear group,
I want to implement a solution to the
following link:
http://acmicpc-live-archive.uva.es/nuevoportal/dat
a/p2006.pdf
As a beginning I am trying to implement this
little sample program which will
delete the repeated strings in two set of
strings.
The code:
#include<stdio.h>
#include<stdlib.h>
enum str_match{UN_MATCHED=-1,MATCHED};
unsigned my_strmatch(const char *pattern1,char
*pattern2) {
while(pattern1 != '\0' && pattern2++ !=
'\0') if( pattern1 == pattern2)
return MATCHED;
else
return UN_MATCHED;
}
int main(void)
{
char *str1 = "grammer is a important for a
language isn't it"; char *str2 = "grammer is a dufficult in a
language isn't it"; while(str1 != '\0' && str2 != '\0')
{
if(my_strmatch(str1,str2) ==
MATCHED) free(str1);
}
printf("the remaining string are %s",str1);
return 0;
}
I know that I am making a very basic error in
pointer memory allocation which
I am not sure. Can any one help me out in doing
this. Don't just write the program
since that will be too simple for you people.
Just give me a hint. Thanks.
<replay made in attachment>
you can't free string allocated with no malloc.
so char *c = "........";
free(c);
is not allowed.
hth
Ruchir
</replay made in attachment>
Ok, I just made the following change.
code:
#include<stdio.h>
#include<stdlib.h>
enum str_match{UN_MATCHED=-1,MATCHED};
unsigned my_strmatch(const char *pattern1,char
*pattern2)
{
while(pattern1 != '\0' && pattern2++ !=
'\0')
if( pattern1 == pattern2)
return MATCHED;
else
return UN_MATCHED;
}
int main(void)
{
char *str1 = malloc(sizeof *str1);
char *str2 = malloc(sizeof *str2);
if(!str1 || !str2)
{
printf("malloc error\n");
exit(1);
}
str1="grammer is a important for a language
isn't it";
str2 = "grammer is a dufficult in a language
isn't it";
while(*(str1++) != '\0' && *(str2++) != '\0')
{
if(my_strmatch(str1,str2) ==
MATCHED)
free(str1);
}
printf("the remaining string are %s",str1);
return 0;
}
end code:
I post incremented the str1 and str2 and checked
the value of the two variable.
(operator preceding rules)
If I make the following change:
while((*str1)++ != '\0' && (*str2)++ != '\0')
that is , first de-refer the pointer and apply
the post increment operator
the program shows a run time error. Can any one
explain me why?
And though the above program is correct it does
not lead to the core issue which
is deleting the matched string. Instead it frees
the whole strings. I need to work
over it.The program does not show any error but
simply does not print anything.
