G20 Answer

/* declare the Point type */
typedef struct
{
  int x, y;
} Point;

/* declare the Color type */
typedef struct
{
  int red, green, blue;
} Color;

/* declare the Triangle type */
typedef struct
{
  Point p0, p1, p2;
  Color color;
} Triangle;

/* function to print a Color */
void printColor( Color *c )
{
  printf("%3d red, %3d grn, %3d blu", c->red, c->green, c->blue );
}

/* function to print a Point */
void printPoint( Point *p )
{
  printf("(%d, %d) ", p->x, p->y );
}

/* function to print a Triangle */
void printTriangle( Triangle *t )
{
  printf("Points: ");
  printPoint( &t->p0 ); printPoint( &t->p1 ); printPoint( &t->p2 );
  printf("\nColor: ");
  printColor( &t->color );
  printf("\n");
}

/* function to initialize a Triangle */
void setTriangle( Triangle *t, Point p0, Point p1, Point p2, Color c )
{
  t->p0 = p0;
  t->p1 = p1;
  t->p2 = p2;
  t->color  = c;
}

/* are two Points equal? */
int equalPoint( Point *ptA, Point *ptB )
{
  return ptA->x==ptB->x && ptA->y==ptB->y ;
}

int equalTriangle( Triangle *a, Triangle *b )
{
  if      ( equalPoint( &a->p0, &b->p0 ) && equalPoint( &a->p1, &b->p1 ) && equalPoint( &a->p2, &b->p2 ) )
    return 1;
  else if ( equalPoint( &a->p0, &b->p0 ) && equalPoint( &a->p1, &b->p2 ) && equalPoint( &a->p2, &b->p1 ) )
    return 1;
  else if ( equalPoint( &a->p0, &b->p1 ) && equalPoint( &a->p1, &b->p0 ) && equalPoint( &a->p2, &b->p2 ) )
    return 1;
  else if ( equalPoint( &a->p0, &b->p1 ) && equalPoint( &a->p1, &b->p2 ) && equalPoint( &a->p2, &b->p0 ) )
    return 1;
  else if ( equalPoint( &a->p0, &b->p2 ) && equalPoint( &a->p1, &b->p0 ) && equalPoint( &a->p2, &b->p1 ) )
    return 1;
  else if ( equalPoint( &a->p0, &b->p2 ) && equalPoint( &a->p1, &b->p1 ) && equalPoint( &a->p2, &b->p0 ) )
    return 1;
  else
    return 0;
}

int main(int argc, char *argv[])
{
  Point p1 = { 12, 45 };
  Point p2 = { 12, 92 };
  Point p3 = {  6, 56 };
  Color c1 = {255, 123, 100 };
  Color c2 = { 90,   3, 133 };

  Triangle tA, tB;
  setTriangle( &tA, p2, p1, p3, c2 );
  setTriangle( &tB, p3, p1, p2, c2 );

  if ( equalTriangle( &tA, &tB ) )
    printf("Equal Triangles:\n" );
  else
    printf("Not Equal Triangles:\n");

  printf("\t"); printTriangle( &tA );
  printf("\n");
  printf("\t"); printTriangle( &tB );
  printf("\n");

  system("pause");
  return 0;
}

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