CSC 122: Computer Science II, Spring 2005

Haskell Homework

Due Tuesday, March 15, in class

Write the following functions. Turn in a printout of your functions. If appropriate you may reuse functions that you have already written on this sheet to write other functions on this sheet.

1. Write a Haskell function sumUp that takes two parameters (both integers). The function should return the sum of all the numbers between the two parameters (inclusive). You cannot make any assumptions about the order of the parameters. For example, sumUp( 5, 3 ) should return 12.
2. Write a Haskell function called count that takes two parameters (a list and an item). The function should return the number of times that the given item occurs in the list. For example, count( [1, 3, 2, 3], 3 ) should return 2.
3. Write a Haskell function called remove that takes two parameters (a list and an item). The function should return a list that would result from removing the first copy of item from the list (all other copies of item should remain). If item is not in the list, return the list unchanged. For example, remove( [2, 4, 6, 4, 8, 10], 4 ) should return [2, 6, 4, 8, 10].
4. Write a Haskell function called insert that takes two parameters (a list and a number). You may assume that the list consists of 0 or more numbers that are in order. The function should return a list that would result from inserting the number into the list into the appropriate place to keep the list in order. For example, insert( [2, 4, 6, 8], 5 ) should return [2, 4, 5, 6, 8].
5. Write a Haskell function called insertSort that takes one parameter (a list of numbers). The function should return the list that would result from sorting the list using insertion sort. Note: the insert function should be useful here, as would an auxiliary function.
6. Write a Haskell function called declist that takes one parameter (a list of numbers). The function should return a list of numbers with each number one less that the corresponding number in the original list. For example, declist( [1, 2, 3, 4] ) should return [0, 1, 2, 3].
7. Write a Haskell function called position that takes as parameters an integer and a list of numbers. The function will return the position of the integer in the list, where the first position is 1. For example, position( 3, [1, 3, 4, 5] ) should return 2.
8. Challenge: Modify problem 7 so that it returns the number 0 if the integer is not in the list.

DePauw University, Computer Science Department, Spring 2005
Maintained by Brian Howard (bhoward@depauw.edu). Last updated