Programming paradigm

Programming Paradigms
Bhavin Kamani

Imperative Programming
Instructional
Command
Variable State
Conditions
Loops

Direct
Efficient
Inflexible
Side Effects

Assembly, C
COBOL, Visual Basic

Abstraction
Maintainibility
Learning Curve
Over Engineering

Declarative Programming
"What" instead of "How"
Reduced Side effects
Order of statements not crucial

Domain Specific Languages
Regular Expression

Composability
Concurrency
Learning Curve
Main stream support

LISP, Haskell, Erlang
Closure, Scala, F#

http://www.99-bottles-of-beer.net
JavaScript

Lyrics
99 bottles of beer on the wall, 99 bottles of beer.
Take one down and pass it around, 98 bottles of beer on the wall.
--------------------------------------------------------------------------
--------------------------------------------------------------------------
1 bottle of beer on the wall, 1 bottle of beer.
Take one down and pass it around, no more bottles of beer on the wall.
No more bottles of beer on the wall, no more bottles of beer.
Go to the store and buy some more, 99 bottles of beer on the wall.

Imperative Style
var lyrics = [];
for (var bottles = 99; bottles > 0; bottles--) {
lyrics.push(bottles + " bottles of beer on the wall, "
+ bottles + " bottles of beer");
var next_bottles = ((bottles-1) == 0 ? "no more" : (bottles-1));
lyrics.push("Take one down and pass it around, "
+ next_bottles + " bottles of beer on the wall.");
}
var zero_bottle = "No more";
lyrics.push(zero_bottle + " bottles of beer on the wall, "
+ zero_bottle + " bottles of beer");
lyrics.push("Go to the store and buy some more, "
+ "99 bottles of beer on the wall.");
document.writeln(lyrics.join("<BR>"));

Object-Oriented Style
varBottleSong=function(num_bottles,stanza){
this.num_bottles=num_bottles;
this.stanza=stanza;
};
BottleSong.prototype={
sing:function(separator){
varbeer_form="bottlesofbeer";
for(varbottles=this.num_bottles;bottles>0;bottles--){
this.stanza.addLine(bottles+beer_form+"onthewall,"+bottles+beer_form);
varnext_bottles=((bottles-1)==0?"nomore":(bottles-1));
this.stanza.addLine("Takeonedownandpassitaround,"+next_bottles+beer_form+"onthewall.");
}
varzero_bottle="Nomore";
this.stanza.addLine(zero_bottle+beer_form+"onthewall,"+zero_bottle+beer_form);
this.stanza.addLine("Gotothestoreandbuysomemore,"+this.num_bottles+beer_form+"onthewall.");
returnthis.stanza.write(separator);
}
}
varStanza=function(){
this.lines=[];
};
Stanza.prototype={
addLine:function(line){
this.lines.push(line);
},
write:function(separator){
returnthis.lines.join(separator);
}
}
varsong=newBottleSong(99,newStanza());
document.writeln(song.sing("<BR>"));

Functional Style
var BottleSong = function(num_bottles){
var bottles = function(n){
return (n == 0 ? "no more" : n) + " bottles";
}
this.num_bottles = num_bottles;
this.last_stanza = function(){
return ["No more bottles of beer on the wall, no more bottles of beer.",
"Go to the store and buy some more, 99 bottles of beer on the wall."];
}
this.stanza = function(n) {
var line = [bottles(n) + " of beer on the wall, " + bottles(n) + " of beer."];
line.push("Take one down and pass it around, " + bottles(n-1) + " of beer on the wall.");
return line;
}
}
BottleSong.prototype = {
sing: function(separator){
var bottles = _.range(this.num_bottles,0,-1)
var that = this;
return _.reduce(bottles, function(lyrics, n) {
return lyrics.concat(that.verse_n(n));
},[]).concat(that.verse_0()).join(separator);
}
}
var song = new BottleSong(99);
document.writeln(song.sing("<BR>"));

bottles 0 = "no more bottles"
bottles 1 = "1 bottle"
bottles n = show n ++ " bottles"
verse 0 = "No more bottles of beer on the wall, no more bottles of beer.n"
++ "Go to the store and buy some more, 99 bottles of beer on the wall."
verse n = bottles n ++ " of beer on the wall, " ++ bottles n ++ " of beer.n"
++ "Take one down and pass it around, " ++ bottles (n-1)
++ " of beer on the wall.n"
main = mapM (putStrLn . verse) [99,98..0]
Haskel Solution

(defn bottles-str [n]
(str
(cond
(= 0 n) "no more bottles"
(= 1 n) "1 bottle"
:else (format "%d bottles" n))
" of beer"))
(defn print-bottle [n]
(println (format "%s on the wall, %s." (bottles-str n) (bottles-str n)))
(println "Take one down and pass it around," (bottles-str (dec n)) "on the wall."))
(defn sing [n]
(dorun (map print-bottle (reverse (range 1 (inc n)))))
(println "No more bottles of beer on the wall, no more bottles of beer.")
(println "Go to the store and buy some more," (bottles-str n) "on the wall."))
(sing 99)
Clojure Solution

Programming paradigm

More Related Content

Viewers also liked (19)

Recently uploaded (20)

Programming paradigm