racket

I'm looking to create a function that returns a list of 'n' functions each of which increments the input by 1, 2, 3... n respectively. I use DrRacket to try this out. A sample of expected outcome : > (map (lambda (f) (f 20)) (func-list 5)) (21 22 23 24 25) I'm able to write this down in a static-way : > (define (func-list num) > (list (lambda (x) (+ x 1)) (lambda (x) (+ x 2)) (lambda (x) (+ x 3)) (lambda (x) (+ x 4)) (lambda (x) (+ x 5))) [Edit] Also that a few restrictions are placed on implementation : Only 'cons' and arithmetic operations can be used The func-list should take as input only

I am defining a function binomial(n k) (aka Pascal's triangle) but am getting an error: application: not a procedure; expected a procedure that can be applied to arguments given: 1 arguments...: 2 I don't understand the error because I thought this defined my function: (define (binomial n k) (cond ((or (= n 0) (= n k)) 1) (else (+ (binomial(n) (- k 1))(binomial(- n 1) (- k 1)))))) In Scheme (and Lisps in general), parentheses are placed before a procedure application and after the final argument to the procedure. You've done this correctly in, e.g., (= n 0) (= n k) (- k 1) (binomial(- n 1) (-

I need to implement a procedure called inverse-tree that receives a tree whose nodes data values are numbers and booleans and returns the equivalent tree whose nodes satisfy the following: If the equivalent node of the original tree is a number, then the resulting tree’s node is −1· that node value If the equivalent node of the original tree is a boolean, then the resulting tree’s node is the logical not of that node value Examples: > (inverse-tree ’()) ’() > (inverse-tree ’(5)) ’(-5) > (inverse-tree ’(0)) ’(0) > (inverse-tree ’(#f)) ’(#t) > (inverse-tree ’(#t)) ’(#f) > (inverse-tree ’(-5 (1 (

I have the function below which converts an input of numbers into the partially translated word output of those numbers. Using product and quotient, it adds the word representation of numbers while splitting the number into groups. For example: (number-name 87969087) -> '(87 million 969 thousand 87) (number-name 1000000) -> '(1 million) Im trying to complete my problem by fully translating those numbers which are less than 1000 as well. Im trying to implement a function less-than-1000 which will display those smaller numbers as the list is being constructed as well. Alongside: ;; for less than

I want to show the result of my function as a list not as a number. My result is: (define lst (list )) (define (num->base n b) (if (zero? n) (append lst (list 0)) (append lst (list (+ (* 10 (num->base (quotient n b) b)) (modulo n b)))))) The next error appears: expected: number? given: '(0) argument position: 2nd other arguments...: 10 I think you have to rethink this problem. Appending results to a global variable is definitely not the way to go, let's try a different approach via tail recursion: (define (num->base n b) (let loop ((n n) (acc '())) (if (< n b) (cons n acc) (loop (quotient n b)

I need to write a recursive function in Scheme which takes a list of atoms and reverses it in linear time. I am only allowed to use define, lambda, cons, car, cdr, cond, let, and null? . Here is what I have so far: (define reverse (lambda (lat) (cond ((null? lat) lat) (else (cons (reverse (cdr lat)) (cons (car lat) '())))))) So when I call the function: (reverse '(a b c d)) I get the following output: '(() (((() 4) 3) 2) 1) Any help would be very much appreciated. The problem is that if (reverse (cdr lat)) returns a list eg (3 2) then (cons '(3 2) (1)) turns into ((3 2) 1) . A classical way to

I'm creating a function that consumes a list of numbers and produces the elements in the list that are above average. Below is my code: (define (listlength list) (cond ((empty? list) 0) (else (+ 1 (listlength (rest list)))))) (define (listsum list) (cond [(empty? list) 0] [else (+ (first list) (listsum (rest list)))])) (define (average log) (/ (listsum log) (+ (listlength log) 1))) (define (average-filter log) (cons (cond [(> (first log) (average log)) (first log)] [else (average-filter (rest log))]))) So obviously there is something wrong with my code...Can someone help me? The error message

Define the function iota1(n, m) that takes positive integers n, m with n < m as input, and outputs the list (n,n+1,n+2,...,m) I've tried switching the code around multiple times but cannot seem to get it to function and display a list the right way (define (iota1 n m) (if (eq? n 0) '() (append (iota1 (< n m) (+ n 1)) (list n)))) There's a few oddities to the code you provided, which I've formatted for readability: (define (iota1 n m) (if (eq? n 0) '() (append (iota (< n m) (+ n 1)) (list n)))) The first is that the expression (< n m) evaluates to a boolean value, depending on whether n is less