1. Paradigme de programare Mihai Zaharia
11/11/2018
Introducere
Paradigme de programare
Mihai Zaharia

2. Obiectivele cursului
Intelegerea principalelor paradigme de programare folosite in dezvoltarea aplicatiilor la aceasta ora.
Familiarizarea cu diferite limbaje de programare care implementeaza una sau mai multe paradigme simultan
Stabilirea tipurilor de probleme unde sunt folosite diverse paradigme functie de context
Invatarea unor instrumente noi de programare
Limbajele care vor fi folositea de-a lungul cursului sunt
UML
C/C++
Java,
Java Beans
LabWindows
Python
Haskel
Prolog

3. Criterii folosite in evaluarea activitatii
Participarea la orele de curs si de laborator:
Neparticiparea la mai mult de 14% din laboratoare conduce la refacerea disciplinei
Activitatea de laborator (nu e de ajuns sa iti aduci corpul la laborator = participare) 25%
Teme acasa la majoritatea laboratorelor 25%
Examen final 50% (este o singura nota) defalcat astfel:
Proba de laborator – ELIMINATORIE 25% cu bilete si 2 ore maxim la dispozitie. Un subiect din doua trebuie sa fie indeplinit integral pentru a se putea nota (min 5)
Proba teoretica – 25% - test docimologic - contine si intrebari cu caracter practic specfice laboratorului (min 5)

4. Indatoririle studentului
Cititi materialele recomandate cu o zi inainte de fiecare curs – elaborati o lista de intrebari eventual
Rezolvati temele pe acasa in saptamana in care le-ati primit
Participati la cursuri (suportul de curs livrat va contine numai desenele/cod din slide-uri)
Rezervati un minim de 2-4 ore de studiu individual pe saptamana pentru aceasta materie
Verificati intelegerea teoretica si practica a notiunilor asimilate prin ajutarea colegilor cu raspunsuri legate de partea teoretica sau ajutor (nu tema copiata) in rezolvarea problemelor practice
Ca viitori ingineri este de asteptate sa Respectati codul etic minim al IEEE

5. Sintaxa Defineste simbolurile si gramatica unui limbaj
BNF sau
EBNF
if-statement ::= if ( expression ) statement-block
[ else statement-block ]
statement-block ::= statement ';'
| '{' statement ';' [...] '}'
statement ::= if-statement | assignment-statement |
while-statement | ...etc...

6. Strategii de implementare
11/11/2018
Compilator:
Interpretor:
Hibrid:

7. Compilarea unui program
file.c
main() {
printf("hello");
exit(0); }
Cod sursa
Preprocesor
Analizor Lexical, etc
file.obj
.sym printf
FE048C7138
029845AAAF
...
Object Code
Compilator
Executable
Program
Link-Editor
printf.obj
<obj. code for
printf function>
file.exe
<hardware instructions>
Biblioteci (pentru cod obiect

8. Java: o strategie hibrida
Biblioteci
Executare program
‘Escu.java
Sunt ‘escu!
javac
Hello.class
java
Program sursa Java
compilator
byte code
MVJ:
Verificare byte cod
- Incarcare clase
- interpretor
Java Runtime Environment (JRE)

9. Exemple de erori (Java):
11/11/2018
Exemple de erori (Java):
public int cmmdc ( int v# ) // eroare lexicala {
int z = value
y = v;
while ( y >= 0 )
{ int t = y;
y = z % y;
z = t; }
return y;

10. Executia instructiunilor pe un CPU
…etc…

11. Executarea unui program
11/11/2018
Executarea unui program
Registri interni ll
Cache
RAM
Contorul programului

12. Ce instructiuni de baza poate interpreta un procesor?
LOAD SAVE MOVE ADD MULT COMPARE TEST JUMP TO

13. Java code/bytecode pentru JVM
0: iconst_2 //incepe for
1: istore_1
2: iload_1
3: sipush 1000
6: if_icmpge 44 //comparatia cu 1000
9: iconst_2 //incepe for
10: istore_2
11: iload_2
12: iload_1
13: if_icmpge 31 // compartia cu i
16: iload_1 //incepe if
17: iload_2
18: irem
19: ifne 25 // comparatia cu 0
22: goto 38
25: iinc 2, 1 //j++
28: goto 11
31: getstatic #84; //apel PrintStream
34: iload_1
35: invokevirtual #85; //PrintStream.println:(I)V
38: iinc 1, 1 // i++
41: goto 2
44: return
outer:
for (int i = 2; i < 1000; i++) {
for (int j = 2; j < i; j++)
if (i % j == 0) continue outer; }
System.out.println (i);
De ce nu sunt continue numerele/adresele de la bytecode?

14. Primele incercari de abstractizare
11/11/2018
Primele incercari de abstractizare
Fortran, primul limbaj de nivel înalt,
@echo off cls
echo Press any key to start AProgram.exe!
pause > nul
AProgram.exe %1
if errorlevel 1
goto error
echo AProgram has finished whatever it was doing.
goto end
error: echo Something went wrong with Aprogram
end
PROGRAM EXEMPLU ! VERSION 0.0.
CALL HELLO !apelarea subrutinei HELLO.
CONTAINS !CONTAINS incheie program principal si incepe definirea subrutinelor
SUBROUTINE HELLO !definirea corp SUBROUTINA
WRITE(*,*) "HELLO WORLD!“ ! afisez "HELLO WORLD!" la CONSOLA.
END SUBROUTINE HELLO ! Sfarsit SUBROUTINA
END PROGRAM EXEMPLU !sfarsit PROGRAM

15. Cele mai cunoscute limbaje din generatia a treia
11/11/2018
Cele mai cunoscute limbaje din generatia a treia
Functie de tipul de paradigma folosit in rezolvarea problemelor
Imperative: FORTRAN, COBOL, BASIC, C, Pascal
Functionale: Scheme, Lisp
Limbaje Logice: Prolog
Orientate obiect:
Orientate obiect pure: Java, Python
Orientate obiect si imperative : C++, Perl, Visual Basic

16. Limbaje din generatia a patra
11/11/2018
Acestea sunt deja orientate pe anumite tipuri de aplicatii
SQL pentru baze de date
Limbajul Postscript pentru descrierea unei pagini folosit de imprimante
PDF pentru documente on-line
HTML and PHP pentru continut World Wide Web
Mathematica

17. Exemple - SQL Inserarea unui table intr-o baza de date:
11/11/2018
Exemple - SQL
Inserarea unui table intr-o baza de date:
INSERT INTO angajati(id, Nume, Prenume, functie) VALUES (1445, ‘John’,’Smith',’manager’);
Extragere de informatii functie de un criteriu dintr-un tabel:
SELECT id, Prenume, salariu FROM angajati WHERE ( Job = ‘manager’ );
SQL este considerat a fi declarativ S

18. Ce este o paradigma de programare?
11/11/2018
D1 (generală) Caz exemplar, model, prototip, situaţie ideală, structură tip, arhetip standard ş.a.
D2. (în filozofie, la L.Wittgenstein) Modelele filosofice, acele "tipare" care orientează gândirea noastră în direcţii predeterminate.,
D3 (în filozofia limbajului) Listă de cazuri tipice de jocuri lingvistice prin care putem înţelege conceptul general..."

19. Concepts, Techniques, and Models of Computer Programming (MIT Press, 2004)

20. Paradigme de programare (wiki)
Action Agent-oriented Aspect-oriented Automata-based Component-based Flow-based Pipelined Concatenative Concurrent computing Relativistic programming Data-driven Declarative (contrast: Imperative) Constraint Dataflow Cell-oriented (spreadsheets) Reactive Intensional Functional Logic Abductive logic Answer set Constraint logic Functional logic Inductive logic End-user programming Event-driven Service-oriented Time-driven Expression-oriented Feature-oriented Function-level (contrast: Value-level) Generic Imperative (contrast: Declarative) Procedural Language-oriented Discipline-specific Domain-specific Grammar-oriented Dialecting Intentional Metaprogramming Automatic Reflective Attribute-oriented Homoiconic Template Policy-based Non-structured (contrast: Structured) Array Nondeterministic Parallel computing Process-oriented Programming in the large and small Semantic Structured (contrast: Non-structured) Modular (contrast: Monolithic) Object-oriented (OOP) By separation of concerns: Role-oriented Subject-oriented Class-based Prototype-based Recursive Value-level (contrast: Function-level) Probabilistic

21. Programarea nestructurată
11/11/2018
Bloc continuu
Salt direct
ASM
.model small
.stack 1024
. data
z db ? ; n
MOV
MOV DS, AX
MOV al, 3 ; m=3
ADD al, 5 ; m=m+5
Jmp etl
etl: MOV z,al ; n=5
MOV al,z
MOV ah, 4ch
INT 21h
end start
Basic
10 rem program exemplu
20 m=3
30 m=m+5
40 goto 50
50 n=5
60 m=n
60 end

22. TIOBE Programming Community Index for August 2013
Position Aug 2013
Position Aug 2012
Programming Language
Ratings Aug 2013
Delta Aug 2012
Status 1 2
Java
15.978%
-0.37% A C
15.974%
-2.96% 3 4
C++
9.371%
+0.04%
Objective-C
8.082%
-1.46% 5 6
PHP
6.694%
+1.17% C#
6.117%
-0.47% 7
(Visual) Basic
3.873% 8
Python
3.603%
-0.27% 9 11
JavaScript
2.093%
+0.73% 10
Ruby
2.067%
+0.38%
Perl
2.041%
-0.23% 12 15
Transact-SQL
1.393%
+0.54% 13 14
Visual Basic .NET
1.320%
+0.44%
Delphi/Object Pascal
0.918%
-0.09%
A-- 20
MATLAB
0.841%
+0.31% 16
Lisp
0.752%
-0.22% 17 19
PL/SQL
0.751%
+0.14% 18
Pascal
0.620%
-0.17% A- 23
Assembly
0.616%
+0.11% B 22
SAS
0.580%
+0.06%

23. Cmmdc Structurat in C #include <stdio.h> int main() {
11/11/2018
Cmmdc Structurat in C
#include <stdio.h>
int main() {
int a=1574, b=56, t, cmmdc;
while (b != 0)
t = b;
b = a % b;
a = t; }
cmmdc = a;
printf("Greatest common divisior of %d and %d = %d\n", a, b, cmmdc);
getch();

24. Procedural Java Script cmmdc
function calculate() { var x = 167; var y = 3; var output; output = cmmdc(Math.abs(x), Math.abs(y)) } function cmmdc(x, y) while (y != 0) var z = x % y; x = y; y = z; return x;

25. Functional in C #include <stdio.h> int cmmdc(int u, int v) {
if (v == 0)
return u;
else
return cmmdc (v, u % v); }
int main(void)
int x =9, y=6;
printf("The gcd of %d and %d is %d\n",x,y,cmmdc(x,y));
return 0;

26. Functional cmmdc in Scheme
11/11/2018
Functional cmmdc in Scheme
(define (cmmdc u v)
(if (= v 0) u
(cmmdc v (modulo u v) ) )
Sintaxa Scheme pentru o functie:
( define ( function-name param1 param2 ... )
body of function definition )

27. Functional cmmdc in Scheme
11/11/2018
Functional cmmdc in Scheme
(define (euclid)
(display "enter two integers:")
(let ( (u (read)) (v (read)) )
(display "the gcd of ")
(display u)
(display " and ")
(display v)
(display " is ")
(display (gcd u v))
(newline) )

28. Imperativ in Java: cmmdc
public class oarescare {
private static long cmmdc(long u, long v) {
long remainder;
if (v < 0) v = -v;
while ( v != 0 ) {
remainder = u % v;
u = v;
v = remainder; }
if ( u == 0 ) return 1; // cmmdc(0,x) = 1
else return (u>0)? u : -u; // modul
... Restul clasei nu are importanta

29. Imperativ original:FORTRAN 77
INTEGER FUNCTION IGCD(U,V)
INTEGER U, V, TMP
DO WHILE ( V .NE. 0 )
TMP = V
V = MOD(U,V)
U = TMP
END DO
IGCD = V
RETURN
END
PROGRAM MAIN
WRITE(6,*) "Input two integers:"
READ(5,*) I, J
WRITE(6,100) I, J, IGCD(I,J)
100 FORMAT("GCD of ",I4," and ",I4," is ",I4)
STOP

30. Oop Java cmmdc public class CMMDC { private final int value;
11/11/2018
Oop Java cmmdc
public class CMMDC {
private final int value;
public CMMDC( int value )
{ this.value = value; }
public int cmmdc ( int v ) {
int u = value;
while ( v != 0 ) {
int t = u % v;
u = v;
v = t; }
return u;

31. Cmmdc in programare logica Prolog
11/11/2018
Cmmdc in programare logica Prolog
cmmdc(U, V, U) :- V = 0.
cmmdc(U, V, X) :- not (V = 0),
Y is U mod V,
gcd(V, Y, X).
/* calcul cmmdc(288,60) */
cmmdc(288, 60, X).
consequence :- a, b, c.

32. Paradigmele sunt necesare
11/11/2018
Concluzii
Paradigmele sunt necesare

33. Join the club!