Alternative Implementations of Fractions

typedef struct {
  int numerator,denominator; } fraction;

main()
{
  fraction f;
  f.numerator   = 1;
  f.denominator = 2;
  ...
}

#define numerator   0
#define denominator 1
typedef int fraction[2];

main()
{
  fraction f;
  f[numerator]   = 1;
  f[denominator] = 2;
  ...
}