Update Lecture1.hs

src/Lecture1.hs

@@ -39,6 +39,7 @@ module Lecture1
 its behaviour, possible types for the function arguments and write the
 type signature explicitly.
 -}
+makeSnippet:: String -> String
 makeSnippet limit text = take limit ("Description: " ++ text) ++ "..."
 
 {- | Implement a function that takes two numbers and finds sum of
@@ -54,7 +55,8 @@ Explanation: @sumOfSquares 3 4@ should be equal to @9 + 16@ and this
 is 25.
 -}
 -- DON'T FORGET TO SPECIFY THE TYPE IN HERE
-sumOfSquares x y = error "TODO!"
+sumofSquares:: Int -> Int -> Int
+sumOfSquares x y = (x ^ 2) + (y ^ 2) 
 
 {- | Implement a function that returns the last digit of a given number.
 
@@ -67,7 +69,8 @@ sumOfSquares x y = error "TODO!"
 
 -}
 -- DON'T FORGET TO SPECIFY THE TYPE IN HERE
-lastDigit n = error "lastDigit: Not implemented!"
+lastDigit:: Int -> Int
+lastDigit n = n `mod` 10
 
 {- | Write a function that takes three numbers and returns the
 difference between the biggest number and the smallest one.
@@ -81,7 +84,11 @@ and 1 is the smallest, and 7 - 1 = 6.
 Try to use local variables (either let-in or where) to implement this
 function.
 -}
-minmax x y z = error "TODO"
+minmax:: Int -> Int -> Int -> Int
+minmax x y z = 
+    let max = maximum [x,y,z]
+        min = minimum [x,y,z]
+    in max - min
 
 {- | Implement a function that takes a string, start and end positions
 and returns a substring of a given string from the start position to
@@ -98,7 +105,11 @@ start position can be considered as zero (e.g. substring from the
 first character) and negative end position should result in an empty
 string.
 -}
-subString start end str = error "TODO"
+subString:: Int -> Int -> String -> String
+subString start end str 
+    | start < 0 = 0 end str
+    | end < 0 = ""
+    | otherwise = take (end - start + 1) (drop start str)
 
 {- | Write a function that takes a String — space separated numbers,
 and finds a sum of the numbers inside this string.
@@ -108,7 +119,10 @@ and finds a sum of the numbers inside this string.
 
 The string contains only spaces and/or numbers.
 -}
-strSum str = error "TODO"
+strSum:: String -> Int
+strSum str =
+    let number = map read (words str) :: [Int]
+    in sum number
 
 {- | Write a function that takes a number and a list of numbers and
 returns a string, saying how many elements of the list are strictly
@@ -123,4 +137,8 @@ and lower than 6 elements (4, 5, 6, 7, 8 and 9).
 
 🕯 HINT: Use recursion to implement this function.
 -}
-lowerAndGreater n list = error "TODO"
+lowerAndGreater:: Int -> [Int] -> String
+lowerAndGreater n list =
+    let lower = filter (<n) list
+        greater = filter (>n) list
+    in "Lower: " ++ show lower ++ "\nGreater: " ++ show greater