how to ignore whitespaces in fscanf()

Question

I need to use fscanf to ignore all the white spaces and to not keep it. I tried to use something like the combination between (*) and [^\\n]<

Answer 1

Using a space (" ") in the fscanf format causes it to read and discard whitespace on the input until it finds a non-whitespace character, leaving that non-whitespace character on the input as the next character to be read. So you can do things like:

fscanf(file, " "); // skip whitespace
getc(file);        // get the non-whitespace character
fscanf(file, " "); // skip whitespace
getc(file);        // get the non-whitespace character

or

fscanf(file, " %c %c", &char1, &char2); // read 2 non-whitespace characters, skipping any whitespace before each

from:

Ignoring whitepace with fscanf or fgets?

Answer 2

from the fscanf man page:

   A directive is one of the following:
  ·      A sequence of white-space characters (space, tab, newline, etc.;
          see isspace(3)).  This directive matches  any  amount  of  white
          space, including none, in the input.

so

fscanf(file, " %s\n");

will skip all whitespace before reading in characters.

Answer 3

Your code is crashing because you have a %s in your format specifier in the fscanf call, and you don't pass fscanf a char * to which you want it to write the string it finds.

See http://www.cs.utah.edu/~zachary/isp/tutorials/io/io.html.