// FILE: FractionsCode.c
// Code for testing fraction functions scan, display, add
// Definition of a new type for fractions
typedef struct {    // defines a fraction type
   int numer;   // numerator
   int denom;   // denominator
} fractType;



// Function prototypes

// Function to display a fraction
void displayFract 
   (fractType f);  // IN: fraction to be displayed

// Function to add two fractions and return the sum
void addFract
   (fractType *fResult, // OUT: result of adding two fractions
    fractType fLeftop,  // IN: left operand for addition
    fractType fRightop); // IN: right operand for addition

   // Function to scan in a fraction f in form a / b
   // Stores results in numer and denom components of actual arg
   //    Returns -1 if / not present
   //    Returns 0 if b = 0
   //    Returns 1 if ok
   int scanFract
	(fractType *f);   // OUT: fraction to be scanned in



int main ()
{
   fractType f1, f2, f3;
      int k1, k2;   // flags returned from scanFract

   // Scan in f1 and f2
   k1 = scanFract (&f1);
   k2 = scanFract (&f2);
   if(k1 != 1 || k2 != 1)
   { 
	  printf(" Either fraction f1 or f2 entered incorrectly\n");
	  printf(" Program exits immediately. \n");
	  return (-1);  //exit if either fraction read fails
   }	

   // Display f1 and f2;
   printf ("The value of f1 is :");
   displayFract (f1);
   printf("\n");
   printf ("The value of f2 is :");
   displayFract (f2);
   printf("\n");

   // Add together f1 and f2 and display result
   addFract (&f3, f1, f2);
   printf ("The value of f3 (f1 + f2) is :");
   displayFract (f3);
   printf("\n");

   return;
}  // end main



// Function to display a fraction
void displayFract 
   (fractType f)  // IN: fraction to be displayed
{
   printf("The fraction is %d / %d : \n", f.numer, f.denom);
   // OR you could write the fraction in math notation --
   // printf("The fraction is (%d, %d): \n", f.numer, f.denom);
}  // end displayFract



// Function to reduce a fraction to lowest terms
//    Returns original fraction reduced to lowest terms
fractType simplify 
   (fractType fResult)   // fraction to be simplified
{
   // Not written - example of a function stub
   printf ("Simplify function called.  Not yet written. \n");
   return (fResult);
}  // end Simplify



// Function to add two fractions and return the sum
void addFract 
   (fractType *fResult, // OUT: result of adding two fractions
    fractType fLeftop,  // IN: left operand for addition
    fractType fRightop) // IN: right operand for addition
{
   (*fResult).numer = 
      fLeftop.numer * fRightop.denom 
         + fLeftop.denom * fRightop.numer;
   (*fResult).denom = fLeftop.denom * fRightop.denom; 
   // simplifies result to lowest terms
   (*fResult) = simplify (*fResult);  
   return; 
}  // end addFract



// Function to scan in a fraction f in form a / b
// Stores results in numer and denom components of actual arg
//    Returns -1 if / not present
//    Returns 0 if b = 0
//    Returns 1 if ok
int scanFract
   (fractType *f)   // OUT: fraction to be scanned in
{
   char symbol;  // used to store the symbol between a and b
   int tempdenom;   // temp cell for denom - simplifies code
   printf("Enter a fraction in the form a / b:");
   scanf("%d", &(*f).numer);   // or just use f.numer
   scanf("%c", &symbol);
   if (symbol != '/') return (-1);
   scanf("%d", &tempdenom);
   if (tempdenom == 0) return (0);
   (*f).denom = tempdenom;
   return (1);
}  // end scanFract