/* This program reads molar concentrations
   from the file ph.in until end-of file.
   For each molar concentration mc, it
   computes the corresponding pH using the
   formula

                  pH = -log10( mc )

   It then reports whether the solution is acidic
   (pH < 7) or nonacidic. The output is written
   to the file ph.out.
*/

#include <stdio.h>
#include <math.h>

main()
{
   float mc, ph;
   FILE *fin, *fout;

   fin = fopen( "ph.in", "r" );
   fout = fopen( "ph.out", "w" );

   while ( fscanf( fin, "%f", &mc ) != EOF ) {
      ph = -log10( mc );
      fprintf( fout, "\nMolar concentration = %e\n", mc );
      fprintf( fout, "pH = %f\n", ph );
      if ( ph < 7.0 )
         fprintf( fout, "Acidic\n" );
      else
         fprintf( fout, "Nonacidic\n" );
   }
}