Question

i need to define ‘string-right’
the procedure

(define string-right
  (lambda (x)
    (substring x (quotient (string-length x) 2) (string-length x))))

doesnt work on odd string lengths
but the prcoedure

(define string-right
    (lambda (x)
      (substring x (+ (quotient (string-length x) 2) 1)(string-length x))))

doesnt work on even string lengths. please help. frustrated.

Answer 1

assuming you meant you want the right half of a string without it’s middle:
in quotient (the first option), replace:

(string-length x)

with:

(+ 1 (string-length x))

if length of the string is even, then
floor((length + 1) / 2) = length / 2

otherwise
floor((length + 1) / 2) = (length + 1) / 2

the + 1 part would exclude the middle element

the full solution:

(define string-right
  (lambda (x)
    (substring x (quotient (+ 1 (string-length x)) 2) (string-length x))))