Comment

In the previous two puzzles, Triangle structs directly contained other structs. Another possibility is to have the Triangle struct contain pointers to the other struct types. Here is the picture:

Here are some typedef definitions for this:

typedef struct
{
  int x, y;
} Point;

typedef struct
{
  int red, green, blue;
} Color;

typedef struct
{
  Point *p0, *p1, *p2;
  Color *color;
} TriangleMod;

Here is code that constructs such a TriangleMod struct:

int main()
{
  TriangleMod *trimod;
  
  trimod = (TriangleMod *)malloc( sizeof( TriangleMod ) );
  trimod->p0 = (Point *)malloc( sizeof( Point ) );
  trimod->p1 = (Point *)malloc( sizeof( Point ) );
  trimod->p2 = (Point *)malloc( sizeof( Point ) );
  trimod->color = (Point *)malloc( sizeof( Color ) );
  ...
}

No values have been initialized in the above. This is done by statements like:

  trimod->p0->x = 45;
  triptr->p0->y = 97;