day two

daytwo.rkt

@@ -0,0 +1,32 @@
+#lang racket
+
+(define (square x)
+	(* x x))
+
+(define (sum-arr x)
+	(if (= 0 (length x))
+		0
+		(+ (car x) (sum-arr (cdr x)))))
+
+(sum-arr '(1 2))
+
+(define (map arr func)
+	(if (null? arr)
+		(list)
+		(cons (func (car arr)) (map (cdr arr) func))))
+
+(map '(1 2 3) square)
+
+(define (fold func arr val)
+	(if (null? arr)
+		val
+		(fold func (cdr arr) (func val (car arr)))))
+
+(fold cons '(1 2 3 4) '())
+
+;(cons 1 '(1 2) '()
+
+;(car (list 1 2 3))
+
+;(define (fold-map func)
+; (map