- string-set! string k charprocedure
k must be a valid index of string. String-set! stores char in element k of string and returns an unspecified value.
(define (f) (make-string 3 #\*)) (define (g) "***") (string-set! (f) 0 #\?) ===> unspecified (string-set! (g) 0 #\?) ===> error (string-set! (symbol->string 'immutable) 0 #\?) ===> error