// Fraction structure, using typedef

#include <stdio.h>

typedef struct fraction
{
  int num;
  int denom;

} Fraction;		// new type name

// some useful functions

void PrintFraction(Fraction f);		// pass by value
void InputFraction(Fraction * fptr);	// pass by address

Fraction AddByValue(Fraction f1, Fraction f2);
Fraction AddByAddress(const Fraction* p1, const Fraction* p2);

// Test routine (main)

int main()
{
   Fraction f1 = {0,1}, f2 = {3,4}, f3 = {1,2};
   Fraction r1, r2;
 
   printf("f1 = ");  
   PrintFraction(f1);  
   printf("\tf2 = ");  
   PrintFraction(f2);  
   printf("\tf3 = ");  
   PrintFraction(f3);  

   // Test out the InputFraction funtion
   printf("\n\nInput new fraction for f1: ");
   InputFraction(&f1);
   printf("\nInput new fraction for f2: ");
   InputFraction(&f2);
   printf("\nInput new fraction for f3: ");
   InputFraction(&f3);

   printf("\nNew values:\n");
   printf("\nf1 = ");  
   PrintFraction(f1);  
   printf("\tf2 = ");  
   PrintFraction(f2);  
   printf("\tf3 = ");  
   PrintFraction(f3);  

   // Test out the add functions
   r1 = AddByValue(f1, f2);
   r2 = AddByAddress(&f1, &f3);
   printf("\n\nf1 + f2 = ");
   PrintFraction(r1);

   printf("\nf1 + f2 = ");
   PrintFraction(r2);

   printf("\nf2 + f3 = ");
   PrintFraction(AddByValue(f2, f3));

   printf("\n");
   return 0;
}


void PrintFraction(Fraction f)
{
   printf("%d/%d", f.num, f.denom);
}

void InputFraction(Fraction * fptr)
{
   scanf("%d/%d", &(fptr->num), &(fptr->denom));
}

Fraction AddByValue(Fraction f1, Fraction f2)
// pass by value.  f1 and f2 are copies of the incoming data
{
   Fraction r;			// to store the result
   r.num = f1.num * f2.denom + f2.num * f1.denom;
   r.denom = f1.denom * f2.denom;

   return r;			// returned by value
}

Fraction AddByAddress(const Fraction* p1, const Fraction* p2)
{
   Fraction r;
   r.num = p1->num * p2->denom + p2->num * p1->denom;
   r.denom = p1->denom * p2->denom;

   return r;			// returned by value
}