Activity assignment 1

Activity assignments

Implement following functions. There will be 5 points for each of these functions.

• Create a function that gets a list of tuples - [(Int, Char)]. This function takes these pairs and for each of these pairs (n, a) generates a string where the character a is multiplied n times. The function result is a concatenation of these sub-strings.

create :: [(Int, Char)] -> String

create [(2,'a'), (3,'B')] = "aaBBB"

• Create a function that takes two strings - a and b. It will print how many times the string a contains the string b.

count :: String -> String -> Int

count "AbcAbcabcAbc" "Abc" = 3

• Create a function that gets a string line and a list of pairs - [(Int,Int)]. Each of these pairs contain two indexes (starting from 0) ant it describes a swap between two positions in the original string line. Function returns the original string where all these swaps have been applied.

swapIt :: String -> [(Int,Int)] -> String

swapIt "ABC" [(0,2)] = "CBA"
swapIt "ABCD" [(0,2), (1,3),(0,1),(2,3)] = "DCBA"

• Create a function, that gets two lists of integers. The first list is a lit of indexes to the second argument (starting from 1). The result will be the sum of elements from the second list at positions defined by the first list.

sumIt :: [Int] -> [Int] -> Int

sumIt [3,4,2] [5,6,7,8] = 21