//  File: main5.c
//
//  This file tests out the functions in frac_heap.c

#include <stdio.h>
#include <stdlib.h>
#include "frac_heap.h"


// Compute the greatest common divisor using Euclid's algorithm
//
unsigned int gcd ( unsigned int a, unsigned int b) {

   if (b == 0) return a ;

   return gcd (b, a % b) ;
}


// Print a fraction out nicely
//
void print_frac (fraction *fptr) {

   if (fptr->sign < 0) printf("-") ;

   printf("%d/%d", fptr->numerator, fptr->denominator) ;

}


// Initialize a fraction
//
fraction *init_frac (signed char s, unsigned int n, unsigned int d) {
   
   fraction *fp ;

   fp = new_frac() ;
   fp->sign = s ;
   fp->numerator = n ;
   fp->denominator = d ;

   return fp ;
}


// Add two fractions
// Return value is a pointer to allocated space.
// This must be deallocated using del_frac().

fraction *add_frac(fraction *fptr1, fraction *fptr2) {
   unsigned int lcm, div, g, m1, m2  ;
   fraction *answer ;


   g = gcd(fptr1->denominator, fptr2->denominator) ;
   lcm = (fptr1->denominator / g) * fptr2->denominator ;

   m1 = (fptr1->denominator / g) ;
   m2 = (fptr2->denominator / g) ;
   lcm = m1 * fptr2->denominator ;

   answer = new_frac() ;
   answer->denominator = lcm ;

   if (fptr1->sign == fptr2->sign) {

      answer->sign = fptr1->sign ;
      answer->numerator = fptr1->numerator * m2 + fptr2->numerator * m1 ;

   } else if (fptr1->numerator >= fptr2->numerator) {

      answer->sign = fptr1->sign ;
      answer->numerator = fptr1->numerator * m2 - fptr2->numerator * m1 ;

   } else {

      answer->sign = fptr2->sign ;
      answer->numerator = fptr2->numerator * m2 - fptr1->numerator * m1 ;

   }

   div = gcd(answer->numerator, answer->denominator) ;
   answer->numerator /= div ;
   answer->denominator /= div ;

   return answer ;

}


int main() {
   fraction *fp1, *fp2, *fp3 ;

   init_Heap() ;

   fp1 = new_frac() ;
   fp1->sign = -1 ;
   fp1->numerator = 2 ;
   fp1->denominator = 3 ;

   fp2 = new_frac() ;
   fp2->sign = 1 ;
   fp2->numerator = 1 ;
   fp2->denominator = 4 ;

   fp3 = add_frac(fp1, fp2) ;

   print_frac(fp1) ; 
   printf(" plus ") ;
   print_frac(fp2) ; 
   printf(" = ") ;
   print_frac(fp3) ; 
   printf("\n") ;

   dump_heap() ;
   del_frac(fp2) ;
   dump_heap() ;

   fraction *fp4, *fp5, *fp6 ;
   fp4 = init_frac(1, 8, 42) ;
   fp5 = init_frac(1, 17, 96) ;
   fp6 = add_frac(fp4, fp5) ;
   dump_heap() ;

   return 0 ;
}