/*
 * This code/software is licensed under the 
 * CC-GNU GPL version 2.0 or later.
 *
 * see: http://creativecommons.org/licenses/GPL/2.0/
 * 
 * Author: Florian Streibelt <florian@freitagsrunde.org> 
 *  C-Kurs der Freitagsrunde, TU-Berlin September 2010
 *
 */
#include <stdlib.h>
#include <stdio.h>
#include <string.h>

typedef struct product_t {
  char   *name;
  enum _punit { UNDEF,Pieces, KGrams, Liters} punit;
  union {
      struct{
          int    count;
          double price_per_piece; 
      } ppiece;
      struct{
          double weight;
          double price_per_kilo;
      } pkilo;
      struct {
          double liter;
          double price_per_liter;
      } pliter;
  };
} product;


double calc_price(product *foo){
 double sum=-1;
 printf("type: %i - ", foo->punit);
 switch (foo->punit){
   default:  printf ("ERROR.\n");
                break;
   case KGrams: sum=(foo->pkilo.weight * foo->pkilo.price_per_kilo)/1000;
                break;
   case Pieces: sum=foo->ppiece.count * foo->ppiece.price_per_piece;
                break;
   case Liters: sum=foo->pliter.liter * foo->pliter.price_per_liter; 
                break;
    }
   return sum; 
}


int main(int argc, char** argv){

    product  *moo = (product*) calloc(sizeof(product),1);
    moo->name= (char*) calloc(sizeof(char),12);
    strcpy(moo->name,"Wirsingkohl");
    moo->punit=KGrams;
    moo->pkilo.weight=812;
    moo->pkilo.price_per_kilo=1.29;
    double price = calc_price(moo);

    printf("price: %f \n",price);
}