CSCI 360 - Survey of Programming Languages

Fall 2014

Assignment 7: Functions in Haskell

Download and install the Haskell compiler.
- Useful IDE: HEAT
- Useful book: Real World Haskell
Write recursive Haskell functions to do the following. Save all of the functions in a file called recursive.hs:
- Perform exponentiation of two integers.
```
*Main> pow 5 3
125
```
- Create a list of multiples of x.
```
*Main> multiplesOf 3 5
[3,6,9,12,15]
```
- Given a list of numbers, return a list with each number multiplied by a constant:
```
*Main> multBy 4 [5,2,3,8]
[20,8,12,32]
```
- Given a list, return a list of even numbers only.
```
*Main> evenOnly [1..6]
[2,4,6]
```
- Given a list of numbers, return the product.
```
*Main> productOf [5,7,10]
350
```
- Given a list of numbers, return the smallest value.
```
*Main> smallest [5,2,20,-1,6]
-1
```
- Given a list of numbers, return the reciprocals. Skip zero if present.
```
*Main> reciprocals [4,5,1,0,8]
[0.25,0.2,1.0,0.125]
```
- Given an integral value, return its factorial.
```
*Main> factorial 6
720
```
- Given two sorted lists, return a list containing all of the values from both lists, also sorted.
```
*Main> merge [1,3,6] [2,4,9,10]
[1,2,3,4,6,9,10]
```
- Given a list, return a sorted list.
```
*Main> mergeSort [1,3,6,2,4,9,10]
[1,2,3,4,6,9,10]
```
In a new file called higherOrder.hs, reimplement the following functions using higher-order functions or list comprehensions, and absolutely no recursion:
- multiplesOf
- multBy
- evenOnly
- productOf
- smallest
- reciprocals
- factorial
In another file called infinite.hs, reimplement the following functions using infinite lists, potentially in combination with higher-order functions, and again no recursive function calls. Recursive data structures are, of course, prefectly acceptable:
- pow
- factorial
Your source files should include a type signature for every function.