Thread: sscanf problem...help please!

Didn't think so. Now you can do your stuff.

and of course - it is possible to check the token whether it includes '.'

then - decide whether it is integer... It still can be stored as float, but printed with %.0f format or converted to integer during the printing...

Of cause it will require to store the flag isInteger for each value read...
Or - if all value supposed to be positive - values to be pritnted out as integers can be stored as negetives to indicate this flag...

maybe thre are even better solutions... It's upto you to decide what is suffitient for you...

I'm not sure why you feel the need to have such a large array, but it doesn't matter, you're still using it wrong. A two dimensional array is an array of arrays. Thus, if you want just one element of one of those arrays, you have to use both sets of [ ]. Like so:

Code:

var_data[ i ][ j ] = fltread;

That says: "Place fltread in spot j of array i."


Quzah.

What is datapoint?

Do you mean you have to read up to 20 lines; each line can contain up to 1800 numbers?
Do you really need to store them all or just the min/max/avg?

Originally Posted by victor_miami

Dave thanks for your reply. I fixed that problem. See earlier reply. I'm not looking for anyone to write my code for me. I need help figuring out which c lib functions are appropriate to solve the problems described below.

My new problem is reading lines of data (see the most recent example I posted). The lines are all different...meaning the number of data points on each line varies (there could be only one, there could be as many as 15). The data is a mixture of real and integer numbers all separated by spaces, which may not be an issue since I would store them in a character array. Then I need to recognize when the data ends (the data is always ended by another variable followed by it's data.

Sometimes I try to be a little subtle.

I created an input file that combined both "sections" you posted (see attached file.txt). I was hoping you built and ran the code I posted (see my results in the attached results.txt). What I thought you ought to notice in the output is that only numeric values after PARAMS were printed. Which is to say that the code distinguished between numbers and text -- which was what I was attempting to show.

Then you might then have discovered that the code that is used to distinguish the two is that call to strtod and subsequent error checking. By taking this bit out of the loop and using it in an if...else, you can handle numbers and text differently.

Code:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int foo(const char *filename);

int main()
{
   foo("file.txt");
   return 0;
}

int foo(const char *filename)
{
   FILE *file = fopen(filename, "r");
   if ( file )
   {
      char line[BUFSIZ];
      int j = 0, reading = 0;
      while ( fgets(line, sizeof line, file) != NULL )
      {
         if ( reading )
         {
            int n;
            char field[20], *end, *text = line;
            while ( sscanf(text, "%19s%n", field, &n) == 1 )
            {
               double value = strtod(field, &end);
               if ( end != field && (*end == '\n' || *end == '\0') )
               {
                  /* It's a number. */
                  j += printf("%s ", field);
                  if ( j > 72 )
                  {
                     j = 0;
                     putchar('\n');
                  }
               }
               else
               {
                  /* It's not a number. */
                  putchar('\n');
                  puts(field);
                  j = 0;
               }
               text += n;
            }
         }
         else if ( strncmp(line, "PARAMS", 6) == 0 )
         {
            reading = 1;
         }
      }
      fclose(file);
      return 1;
   }
   else
   {
      perror(filename);
   }
   return 0;
}

And by the way, this does not care that the "variable name" text sits on a line by itself -- it could just as well be intermixed with the numbers.

And again, in this example I am not storing anything. But notice that if you can print it, you can store it too.

You must pass pointers to the *scanf functions, because it's the only way a function can change what's been passed. Thus, &n passes the address-of (the &) the variable n to the function.

The == 1 is comparing the return value of the function to 1. Read the man page for a description of what the function returns, and what that means.


Quzah.

Choose a copy of the standard.

Originally Posted by c99

n No input is consumed. The corresponding argument shall be a pointer to signed integer into which is to be written the number of characters read from the input stream so far by this call to the fscanf function. Execution of a %n directive does not increment the assignment count returned at the completion of execution of the fscanf function. No argument is converted, but one is consumed. If the conversion specification includes an assignment suppressing character or a field width, the behavior is undefined.

Hammer still visits fairly often, but he's busy.

The "value" variable is a double (please see the code below). Is there a way to assign this to an array of float type variable? (i.e. - var_value[10][1600], where 10 can be up to 10 different variables and the 1600 can be 1600 pieces of data per variable). The reason I need to do this is that I am writing this out to a file and do not want it to appear as double precision. Or am I better off handling it when I write it to the file (at least I think there is a way to do this but I need to first figure out how).

Thanks!

Code:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int foo(const char *filename);

int main()
{
   foo("file.txt");
   return 0;
}

int foo(const char *filename)
{
   FILE *file = fopen(filename, "r");
   if ( file )
   {
      char line[BUFSIZ];
      int j = 0, reading = 0;
      while ( fgets(line, sizeof line, file) != NULL )
      {
         if ( reading )
         {
            int n;
            char field[20], *end, *text = line;
            while ( sscanf(text, "%19s%n", field, &n) == 1 )
            {
               double value = strtod(field, &end);
               if ( end != field && (*end == '\n' || *end == '\0') )
               {
                  /* It's a number. */
                  j += printf("%s ", field);
                  if ( j > 72 )
                  {
                     j = 0;
                     putchar('\n');
                  }
               }
               else
               {
                  /* It's not a number. */
                  putchar('\n');
                  puts(field);
                  j = 0;
               }
               text += n;
            }
         }
         else if ( strncmp(line, "PARAMS", 6) == 0 )
         {
            reading = 1;
         }
      }
      fclose(file);
      return 1;
   }
   else
   {
      perror(filename);
   }
   return 0;
}