Count Occurrences
Write a function in Scheme that counts the number of occurrences of a single item. This function should return a number representing the number of times that item appears in lst.
(define (count lst item)
; Your Code Here
)
And here’s a test to help you out:
(define (test)
(assert-equal (count '(1 2 3) 1) 1)
(assert-equal (count '(1 1 1 1 1) 1) 5)
(assert-equal (count '(1 0 1 0 1) 2) 0))
(define (count lst item)
(cond ((null? lst) 0)
((= (car lst) item) (+ 1 (count (cdr lst) item)))
(else (count (cdr lst) item))))
If lst is empty, then item cannot be inside it so we should return 0. If the first item is equal to item, then we should return 1 plus the number of times that item appears in the rest of the list. Otherwise, we should just return the number of times that item appears in the rest of the list.
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