/*  Planets.c  (c) Kari Laitinen

    http://www.naturalprogramming.com/

    2013-11-27 File created.
    2013-11-27 Last modification.
*/

#include  <stdio.h>

struct Planet
{
   char    planet_name[ 20 ] ;
   double  mean_distance_from_sun ;
   double  circulation_time_around_sun ;
   double  rotation_time_around_own_axis ;
   long    equatorial_radius_in_kilometers ;
   double  mass_compared_to_earth ;
   int     number_of_moons ;
} ;

//  Much of the information given in the following table is
//  relative to the information concerning the Earth. E.g.,
//  Pluto is 39.507 times further from the sun than the Earth.
//  The data concerning the number of moons may be old.

struct Planet planet_table[]  =
{
   { "Mercury",  0.387,   0.241,  58.815,  2433,   0.05,  0  },
   { "Venus",    0.723,   0.615, 224.588,  6053,   0.82,  0  },
   { "Earth",    1.000,   1.000,   1.000,  6379,   1.00,  1  },
   { "Mars",     1.523,   1.881,   1.029,  3386,   0.11,  2  },
   { "Jupiter",  5.203,  11.861,   0.411, 71370, 317.93, 16  },
   { "Saturn",   9.541,  29.457,   0.428, 60369,  95.07, 18  },
   { "Uranus",  19.190,  84.001,   0.450, 24045,  14.52,  5  },
   { "Neptune", 30.086, 164.784,   0.657, 22716,  17.18,  2  },
   { "Pluto",   39.507, 248.35,    6.410,  5700,   0.18,  0  }
} ;


int main()
{
   struct Planet*  planet_in_table  ;
   char     planet_name_from_user[ 20 ] ;

   printf( "\n This program can give you information about the"
           "\n planets in our solar system. Give a planet name: " ) ;

   gets( planet_name_from_user ) ;

   planet_in_table  =  planet_table ;

   //  Memory addresses are converted to type int in the following
   //  complex boolean expression. That was required in order to make
   //  this program work with the MinGW C++ compiler.

   //  It seems that pointer arithmetics work differently in different
   //  compilers. Again, a very good reason not to use pointers in programs.

   while ( ( (int) planet_in_table  <
                     (int) planet_table + sizeof( planet_table )  ) &&
           ! ( strstr( planet_in_table -> planet_name,
                       planet_name_from_user ) ) )
   {
      planet_in_table  ++  ;
   }

   if ( strstr( planet_in_table -> planet_name,
                planet_name_from_user ) )
   {
      printf( "\n %s orbits the sun at an average distance of %.3f kilometers."
              "\n It takes %.3f years for %s to go around the Sun once."
              "\n The radius of %s is %d kilometers.\n",
              planet_in_table -> planet_name,
              ( planet_in_table -> mean_distance_from_sun ) * 149500000,
              planet_in_table -> circulation_time_around_sun,
              planet_in_table -> planet_name,
              planet_in_table -> planet_name,
              planet_in_table -> equatorial_radius_in_kilometers ) ;
   }
   else
   {
      printf( "\n Sorry, could not find information on %s.\n",
              planet_name_from_user ) ;
   }
}