#lang racket

(define (new-if predicate then-clause else-clause)
  (cond (predicate then-clause)
       (else else-clause)))

(new-if (= 2 3) 0 5)
(new-if (= 1 1) 0 5)


#lang racket

(define (sqrt-iter guess x)
  (new-if (good-enough? guess x)
guess
  (sqrt-iter (improve guess x)
            x)))

(new-if (= 2 3) 0 5)
(new-if (= 1 1) 0 5)
(sqrt-iter 5)