Exercicios3.hs

module Exercicios4 where

-- 1
media :: [Double] -> Double
media z = (foldl (\x y -> x + y) 0 z)

-- 2
pares :: [Int] -> [Int]
pares x = filter (\y -> mod y 2 == 0) x

impares :: [Int] -> [Int]
impares x = filter (\y -> mod y 2 /= 0) x

-- 3
data Correncia = Real | Dolar deriving (Show, Eq)
  
data Dinheiro = Dinheiro {
    valor     :: Double,
    correncia :: Correncia
  } deriving Show

converte :: Dinheiro -> Double
converte (Dinheiro x Real) = x * 4.82 
convete (Dinheiro x Dolar) = x / 4.82

filtraDolar :: [Dinheiro] -> [Dinheiro]
filtraDolar z =  filter(\(Dinheiro x y) -> y == Dolar) z

somaDolares :: [Dinheiro] -> Double
somaDolares x = foldl (\z (Dinheiro a b)-> a + z) 0 (filtraDolar x)