README file

To test the following programs at levels 1 and 3, type

	% make all
	% make test

Description of the programs:

1) line3d.cc

   This determines the relative disposition of the following two lines:

          L1 : (0, 0, 0) --- (sqrt(i), sqrt(j), 1) and
          L2 : (1, 1, 0) --- (sqrt(i)+1, sqrt(j)+1, 1)

   where i, j are in the range [0, 10).  These two lines must satisfy
   exactly one of the following predicates:

   	"isSkew", "isParallel" and "intersect".

   The correct answer should be "isSkew" in all cases.  
   But 10 of the answers are wrong at level 1.

2) line2d.cc

   This computes the intersection point of the plane 

 		P: sqrt(2)*x + y + z - 1 = 0

   with the line:

               L[i,j] : (0, 0, 0) --- (sqrt(i), j*sqrt(j), 3)

   where i, j are in the range [0, 10).  Let P[i,j] be the intersection
   point.  We then evaluates the predicate

		"is P[i,j] on the plane P?"

   The correct answer should be "yes" in every case.
   But 27 of the answers are wrong at level 1.

