G14 Answer

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

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

/* function to construct a Color */
void setColor( Color *c, int r, int g, int b )
{
  if ( r<0 || r>255 ) r = 0;
  if ( g<0 || g>255 ) g = 0;
  if ( b<0 || b>255 ) b = 0;

  c->red   = r;
  c->green = g;
  c->blue  = b;
}

int main(int argc, char *argv[])
{
  /* declare and initialize two Colors */
  Color grass, sky;

  setColor( &grass, 50, 200, 100 );
  setColor( &sky,  100, 100, 250 );

  /* print values */
  printColor( &grass );
  printColor( &sky );

  system("pause");
  return 0;
}

Comments: The set function does not allow out of range values, but does no error reporting.