// FILE: fractions.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 ("The value of f2 is :");
      displayFract (f2);

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

	return (0);
   }



// Function to display a fraction
void displayFraction 
   (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);
   }



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



// Function to add two fractions and return the sum
void addFraction 
   (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 (0); 
   }


   // 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 scanFraction
	(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);
      scanf("%c", symbol);
      if (symbol != '/') return (-1);
      scanf("%d", &tempdenom)
      if (tempdenom == 0) return (0);
      (*f).denom = tempdenom;
      return (1);
   }