Question

Please write below functions in HASKELL functional programming language and remember to include both the (1) function declaration, and (2) function definition.

1. Write a function sumLastPart which, only using library functions, returns the sum of the last n numbers in the list, where n is the first argument to the function.
sumLastPart :: Int -> [Int] -> Int

Answer 1

import Data.List
sumLastPart :: Int -> [Int] -> Int

sumLastPart n = sum . take n . reverse

EXPLANATION:

First we are importing the Data.List library for list functions.

Second line is function declaration where sumLastPart takes an int and a list of int and returns an int.

Third line is function defination. First it will reverse the list and then take first n elements of that reversed list and sum them up to produce the result.