Thread: Simple Line Parsing

Originally Posted by AngKar

But I want to access each element of buffer as integer(e.g. I want 1,2,3 as integers separately).

If you are parsing a whitespace-delimited file of numbers, I would instead do something like this.

Code:

#include <stdio.h>

int main(void)
{
   static const char filename[] = "file.txt";
   FILE *file = fopen(filename, "r");
   if ( file )
   {
      int value[20];
      size_t i, size;
      for ( i = 0; i < sizeof value / sizeof *value; ++i )
      {
         if ( fscanf(file, "%d", &value[i]) != 1 )
         {
            break;
         }
      }
      fclose(file);

      for ( size = i, i = 0; i < size; ++i )
      {
         printf("value[%lu] = %d\n", (long unsigned)i, value[i]);
      }
   }
   return 0;
}

/* file.txt
1 2 3
1 2 4
2 3 4
*/

/* my output
value[0] = 1
value[1] = 2
value[2] = 3
value[3] = 1
value[4] = 2
value[5] = 4
value[6] = 2
value[7] = 3
value[8] = 4
*/

[edit]

Originally Posted by AngKar

I'm using buffer[0] (expecting to find the string "1")

You'd likely want buffer.

Originally Posted by AngKar

But could you please explain where you are taking care of " " (space) and "\n" (newline)?

With the %d. Leading whitespace is ignored; the trailing whitespace is not part of a number so it breaks the conversion, and this whitespace becomes leading whitespace for the next number. Both a space ' ' and a newline '\n' are whitespace, as is a tab '\t' and others like '\r' and '\v'.

If each line will have a different number of values, say like this:

Code:

1 2 3
1
2 4
2 3 4

then I might suggest something else that may be closer to your previous attempt with reading lines -- but using %d in a sscanf loop: sort of a cross between your last version and my last post.