Haskell Programming -- 1. Fill in the gaps. Complete the following definitions.

Question

Haskell Programming

-- 1. Fill in the gaps. Complete the following definitions. It does not

-- matter what the definitions do as long as they are type correct. For e1, e2,

-- e5, and e7, this means uncommenting the type declaration and replacing the ? with

-- type(s) correspond to the definitions directly below them. For e3, e4,

-- e6, and e8, this means replacing the undefined with an expression of appropriate type.

--

-- Note: you should complete each definition one at a time.

--e1 :: ?

e1 = [True,False,True]

--e2 :: ?

e2 = [[1,2],[3,4]]

e3 :: (Char,Bool)

e3 = undefined

e4 :: [(String,Int)]

e4 = undefined

--e5 :: ? -> ?

e5 n = n*2

e6 :: Int -> Int -> Int

e6 = undefined

--e7 :: ? -> ?

e7 (x,y) = (y,x)

e8 :: a -> (a,a)

e8 = undefined

Explanation / Answer

e1 :: [Bool]

e1 = [True,False,True]

e2 :: Num t => [[t]]

e2 = [[1,2],[3,4]]

e3 :: (Char,Bool)

e3 = ('a',True)

e4 :: [(String,Int)]

e4 = [("hello",10),("world",20)]

e5 :: Num a => a -> a

e5 n = n*2

e6 :: Int -> Int -> Int

e6 a b = a+b

e7 :: (t1, t) -> (t, t1)

e7 (x,y) = (y,x)

e8 :: a -> (a,a)

e8 x = (x,x)

Explaination:

1. e1 is a list of Bool

2.e2 is a list of list of Num

3.for e3 we are declaring a return type of the form (Char,Bool)

4.for e4 we are declaring a return type of the form (String,Int)

5.e5 takes a Num and returns square of it.

6.for e6 we can define any function that takes Int and Int as input and returns an Int

7.we are swapping x and y so the types also get swapped

8.e8 just repeat some element x in a tuple

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