Difference between revisions of "Activity assignment 1"

Revision as of 10:23, 11 November 2019

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"

@@ Line 21: / Line 21: @@
 * Create a function that gets a string <code>line</code> and a list of pairs - <code>[(Int,Int)]</code>. Each of these pairs contain two indexes (starting from 0) ant it describes a swap between two positions in the original string <code>line</code>. Function returns the original string where all these swaps have been applied.
 <syntaxhighlight lang="Haskell" >
-count :: String -> String -> Int
+swapIt :: String -> [(Int,Int)] -> String
 </syntaxhighlight>
 <syntaxhighlight lang="Haskell" class="myDark" >
-count "AbcAbcabcAbc" "Abc" = 3
+swapIt "ABC" [(0,2)] = "CBA"
+swapIt "ABCD" [(0,2), (1,3),(0,1),(2,3)] = "DCBA"
 </syntaxhighlight>