Another example of sscanf function

**lsatenstein** · 01-26-2016

Please add the following to the sscan discussion example (thread from 2005)

There are times that we have a line of test as:

line[]= "xyz= "abc"; or
line[]=xyz='abc'; or
line[]= xyz=abc;

AND we want to select out the left and right of the equal sign into two variables. With the sscanf()

Code:

 
char *left;
char *right;
//we want *left=xyz; and *right=abc;

Here is an example of sscanf that does just that for right with/out quotes. 

 if (   sscanf (line, "%[^=] = "%[^"]"", left, right) == 2
     ||  sscanf (line, "%[^=] = '%[^\']'",   left, right) == 2
     ||  sscanf (line, "%[^=] = %[^;#]",    left, right) == 2) 
{
      do_your_thing(left,right);
}

The sscanf returns an integer, the number of items picked out. We stop after the first successful scan.

**Matticus** · 01-26-2016

Perhaps you can post a link to the thread you are referring to.

**algorism** · 01-26-2016

Your example has an unmatched double-quote.
Your code has unescaped double-quotes in the first sscanf format.
You haven't defined any space for left and right (they can't just be pointers to nowhere).
(And you should limit the sscanf string inputs to one-less-than their sizes.)

The general problem with using sscanf to do this is that you can't ignore escaped quotes within
the containing quotes. greeting = "hello "there""

Code:

#include <stdio.h>

int main() {
  char line[1024], left[256], right[256];

  while (fgets(line, sizeof line, stdin) != NULL) {
    if (   sscanf (line, "%255[^=] = \"%255[^\"]\"",  left, right) == 2
        || sscanf (line, "%255[^=] = '%255[^']'",     left, right) == 2
        || sscanf (line, "%255[^=] = %255[^ \t\n;#]", left, right) == 2) 
    {
            printf("[%s] [%s]\n", left, right);
    }
  }

  return 0;
}

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