Programming Language Paradigms - Quicksort Example

• Remember quicksort:
• Split list into 2 parts
• Recursively sort parts
• Join 2 parts


• Imperative Paradigm - Programs specify commands to do
• Programs specify what to do
• Procedural and OO languages
• Java, Ada, C, C++, Perl, ...


• Java quicksort
• Another Java quicksort


• Declarative Paradigm - Functional Languages
• Quicksort in Haskell


• Declarative Paradigm - Logic Languages
• Quicksort in Prolog


• A simple Prolog example:

Rules, facts, queries:

grandparent(X, Z) :- parent(X, Y), parent(Y, Z).

parent(jill, bill).
parent(bob, bill).

parent(adam, bob).

% Queries ...

male(bob).

father(X, Y) :- parent(X,Y),
                male(X). 

% Queries ...