asked on

scanf scan fields

1. What is the correct syntax of the scan field for scanning all characters that are NOT an open-bracket character ('[')? Is there any documentation about how to use the '[' character within the delimiter brackets of scanf?

2. I'd like to scan a line and read into a string, from the first bracket-open char to the first bracket-close (including the brackets). How can this be done with a single sscanf call?

Norbert

As I know there is no chance to use scanf for that but here is a little bit code that does the work

char* Extract(char* CompleteString)
{
char *Start,*Stop,*Result;
int length;
Start=strchr(CompleteString.'[');
if(!Start)
{
printf("no \"[ \" within the string %s",CompleteString);
return NULL;
}
else
{
Stop=strchr(CompleteString.']');
if(!Stop)
{
printf("no \"] \" within the string %s",CompleteString);
return NULL;
}
}
length=Stop-Start;
result=(char*)malloc(length);
strncpy
for(i=0;i<length;i++)
{
result[i]=Start[i];
}
return result;
}

gil_mo

ASKER

Norbert, thanks so much for your effort in supplying the code.
However, I am looking for EXACT answers to both (1) and (2), not ANYTHING else.

bernfarr

I think this is reasonably well documented in the book:
C: A Reference Manual
Samuel Harbison and Guy Steele
(this is the C Bible as far as I'm concerned)

Given that you can read a single [ character with "%[[]", have you tried "%[^[]" as a way of reading any character that is not a [ ?

I think your second part can be solved by reading three strings and combining them following the scanf call. Something like:
char sz1[8], sz2[300], sz3[8];
char szAll[316];

scanf( "%[[]%[^]]%[]]", sz1, sz2, sz3 );
sprintf( szAll, "%s%s%s", sz1, sz2, sz3 );

The sprintf() is expensive, you could strcpy and strcat the strings instead.

bernfarr

gil_mo did what I suggest cover it or not?

newexpert

How about
#define MAX_CHARS_PER_LINE (number here)

fgets(line, MAX_CHARS_PER_LINE, stdin);
sscanf(line, " %*[[]%[^]]%*[]] ", your_string);

/* in the sscanf string. the first space tells scanf to ignore any white space (\n, space, tab). %*[[] read and discard [.
%[^]] read until ] is reached (not read though). %*[]] read and discard ], and now you have your_string. */

gil_mo

ASKER

bernfar, newexpert:
Your suggested format string would not work for lines like:
" abc [[WSA ] " . The expected output of such a line is:
"[[WSA ]" (Please read my question carefully!)

I guess that reading once into a string would not be possible.

ozo

sscanf(" abc [[WSA ] ","%*[^[]%[^]]%[]]",sz1,sz2);
printf("%s%s\n",sz1,sz2);

gil_mo

ASKER

ozo, that would scan all closing brackets. I would replace the last format specifier with "%*c" to skip the first closing bracket and then concatenate the sz1 with "]".

bernfarr, since you had answered the question about the syntax, I'd accept this answer again (drop the second part).

ozo

sscanf(" abc [[WSA ]] ","%*[^[]%[^]]%1[]]",sz1,sz2)

ASKER CERTIFIED SOLUTION

bernfarr

membership

This solution is only available to members.

To access this solution, you must be a member of Experts Exchange.

Start Free Trial