Thread: Question regarding reading data from file into arrays

Code:

#include <stdio.h>

int lines,i;
double *t, *x, *P;

int main(int argc, const char *const *argv)
{
   if ( argc > 1 )
   {
      FILE *file = fopen(argv[1], "r"); /* Get filename from command line. */
      if ( file )
      {
         int ch, prev = '\n' /* so empty files have no lines */, lines = 0;
         while ( (ch = fgetc(file)) != EOF ) /* Read all chars in the file. */
         {
            if ( ch == '\n' )
            {
               ++lines; /* Bump the counter for every newline. */
            }
            prev = ch; /* Keep a copy to later test whether... */
         }
         fclose(file);
         if ( prev != '\n' ) /* ...the last line did not end in a newline. */
         {
            ++lines; /* If so, add one more to the total. */
         }
         printf("lines = %d\n", lines);
      }
      else
      {
         perror(argv[1]);
      }
   }

   t = (double *) malloc (lines * sizeof(double));
   x = (double *) malloc (lines * sizeof(double));
   P = (double *) malloc (lines * sizeof(double));

   {
      FILE *file = fopen(argv[1], "r");
      if ( file )
      {
	double temp1, temp2, temp3;
	for(i = 0; i < lines; i++)
	  {
	    fscanf(file, "%lf %lf %lf", &temp1, &temp2, &temp3);
	    t[i] = temp1;
	    x[i] = temp2;
	    P[i] = temp3;
	    fprintf(stderr, "%lf %lf %lf\n", t[i], x[i], P[i]);
	  }
	fclose(file);
      }
      else
      {
         perror(argv[1]);
      }
   }
   return 0;
}

Why doesn't this one work

there are three lists in file that I need to read into the arrays and print out in a different file, for now file.stdout, but it is empty when I run the program, why?

haha, just googled it :P thanks for that btw