cet_Test1_reqs

write a program for evaluating e = sqrt(x+y) - sqrt(x-y)
	x+y and x-y need to be abs val first
reqs:
 the main program reads Integers x, y, d
 a subroutine sqrt with argument n will approximate the result by repeteadly
 trying
  sqrt(n) = m, m being the max value
  n - m^2 <= d

 a subroutine mod(n) that returns
  n if n >= 0
  -n if n < 0