How do I make a recursive list that checks company rankings?

Posted by Sera on Stack Overflow See other posts from Stack Overflow or by Sera
Published on 2011-01-09T17:41:58Z Indexed on 2011/01/09 18:53 UTC
Read the original article Hit count: 159

Filed under:

list

|

recursion

|

prolog

I have a set of companies in rank order. I want my rule to check if the companies in a specified list are in rank order, and for the rule to recur until all companies in the list have been checked.

I currently have the following:

isOrder([]).
isOrder([COM1,COM2|T]) :-
    rank(COM1,D), rank(COM2,E),
    D<E,
    print("in order"),
    isOrder([COM2|T]).

However, this does not seem to work. Sometimes, the recursion goes on forever without ending, and sometimes the recursion doesn't work at all. This is when I vary the code to try and get the correct answer.

Can anybody help me? I have just started Prolog and my understanding of it is severely limited. Any help would be greatly appreciated.

© Stack Overflow or respective owner

Related posts about list

kernel module compiling error

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
sh@ubuntu:/home/ccpp/helloworld$ make gcc-4.6 -O2 -DMODULE -D_KERNEL_ -W -Wall -Wstrict-prototypes -Wmissing-prototypes -isystem /lib/modules/`uname -r`/build/include -c -o hello-1.o hello-1.c hello-1.c:4:0: warning: "MODULE" redefined [enabled by default] <command-line>:0:0: note: this is… >>> More
SEO: Nested List vs List, Split Over Divs vs Definition List

as seen on Pro Webmasters - Search for 'Pro Webmasters'
From an SEO perspective which, if any, is better: Option 1: Nested lists with h2 tags <ul id="mainpoints"> <li><h2>Powerful Analysis</h2> <ul> <li>Charting and indicators</li> <li>Daily trading signals</li> … >>> More
ASA hairpining: I basicaly want to allow 2 spokes to be able to communicate with each other.

as seen on Server Fault - Search for 'Server Fault'
ASA Spoke to Spoke Communication I have been looking at spke to spoke comms or "hairpining" for months and have posted on numerouse forums but to no avail. I have a Hub and spoke network where the HUB is an ASA Firewall version 8.2 * I basicaly want to allow 2 spokes to be able to communicate with… >>> More
How to remove a package entirely?

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
Hi I'm quite new to Linux, but before using it I was hearing that Windows programs, after uninstallation, leaves a lot of remains on the hard disc, and Linux removes all. I'm using Ubuntu 10.04. To uninstall packages I'm using sudo apt-get autoremove application_name or sudo aptitude purge application_name… >>> More
Update a list from another list

as seen on Stack Overflow - Search for 'Stack Overflow'
I have a list of users in local store that I need to update from a remote list of users every once in a while. Basically: If a remote user already exists locally, update its fields. If a remote user doesn't already exist locally, add the user. If a local user doesn't appear in the remote list, deactivate… >>> More

Related posts about recursion

tail recursion vs. forward recursion

as seen on Stack Overflow - Search for 'Stack Overflow'
Can someone give me the difference between these two kinds recursions and example? specifically in ocaml. Thanks >>> More
Are there advantages for using recursion over iteration - other than sometimes readability and elegance?

as seen on Programmers - Search for 'Programmers'
I am about to make two assumptions. Please correct me if they're wrong: There isn't a recursive algorithm without an iterative equivalent. Iteration is always cheaper performance-wise than recursion (at least in general purpose languages such as Java, C++, Python etc.). If it's true that recursion… >>> More
Python recursive function error: "maximum recursion depth exceeded"

as seen on Stack Overflow - Search for 'Stack Overflow'
I solved Problem 10 of Project Euler with the following code, which works through brute force: def isPrime(n): for x in range(2, int(n**0.5)+1): if n % x == 0: return False return True def primeList(n): primes = [] for i in range(2,n): if isPrime(i): … >>> More
Dynamic Programming Recursion and a sprinkle of Memoization

as seen on Stack Overflow - Search for 'Stack Overflow'
I have this massive array of ints from 0-4 in this triangle. I am trying to learn dynamic programming with Ruby and would like some assistance in calculating the number of paths in the triangle that meet three criterion: You must start at one of the zero points in the row with 70 elements. Your… >>> More
How does the recursion here work?

as seen on Stack Overflow - Search for 'Stack Overflow'
code 1: public static int fibonacci (int n){ if (n == 0 || n == 1) { return 1; } else { return fibonacci (n-1) + fibonacci (n-2); } } how can you use fibonacci if you haven't gotten done explaining what it is yet? I've been able to understand… >>> More