ST II 2011 Final Paper Answers - පැහැදිලි කිරීම් සමග

[සම්පුර්ණ නෑ. කරන්න පුලුවන්ද බැරිද යන්න අත්හදා බැලීමක් පමණි.]
Question 1 Answers

a.  Java Byte Code is the language that the Java Virtual Machine understands. Java Compiler compiles the source code into the Java Byte Code. Java is platform independent. So once source code compiles into byte code it can execute on any platform wherever Java Virtual Machine is installed.

b. .class is the file type, extension of Java Byte Code

c. By compiling a java source code file we can have the java byte code.

d. int, byte, short, long

e.

i. wrong - It should be corrected as char C1;

ii. correct

iii. wrong - long and int are two different data types.

long m;
int m;

iv. wrong - no such data type call bool. it should be boolean

f.
                Arithmetic Operators     +   -   /   *
                Bitwise Operators            ~  &  |   ^   <<   >>
                Relation Operators          ==  !=  >   <   >=   <=
                Boolean Logical Operators           &  |   ^   ||   &&   !

g.
                i. 23        ගණිතකර්ම ප්‍රමුඛතා පිළිවෙල වන්නේ
                                1. ( )       2. *         3. /         4. +         5. -

ii. -2        % මගින් සංඛ්‍යාවක් බෙදා ඉතිරිය ලබා දේ.

iii. true පළමුව වරහන් සුළු වේ. පහසුව තකා, true=1, false=0, ‘||’=+ සහ ‘&&’=* ලෙස සලකන්න.

iv. 2        >>  shift right.
                shift කරන විට සංඛ්‍යා වල binary අගය ගන්න.
                8 binary කලාම 1000
                right shift කරන විට අදාළ binary සංඛ්‍යාවේ දකුණු පසින් දෙන ලද ඉලක්කම් ප්‍රමාණයක් හලන්න.
                මෙහිදී නම් 1000 à 10
                මේ උත්තරේ decimal කලාම final answer එක ලැබෙනවා. = 2

h.

class DesendingOrder{                 public static void main(String [] hansa){                                 int [] a = new int[3];                                 for(int i=0;i<3;i++){  // command line එකෙන් argument අරන්, array 1 store කරගැනීමට                                                 a[i]=Integer.parseInt(hansa[i]);                                 }                                 int t; // තාවකාලිකව array data එකක් save කර තබා ගැනීමට                                 for(int k=0; k<3; k++){ // descend වීමට යා යුතු වාර ගණන                                                 for(int i=0; i<2; i++){ //array එකේ data, descend order කිරීමට                                                                 if(a[i]<a[i+1]){                                                                                 t = a[i]; // අඩු අගය t වලට save කරයි.                                                                                 a[i] = a[i+1]; // වැඩි අගය, අඩු අගය තිබුණු තැනට සමාන කරයි.                                                                                 a[i+1]=t; // වැඩි අගය තිබුණු තැනට, අඩු අගය සමාන කරයි                                                                 }                                                 }                                 }                                 for(int i=0;i<3;i++){ // descend order වූ array එක display කරයි.                                                 System.out.println(""+a[i]);                                 }                 } } i. import java.util.*; class SplitSentence{                 public static void main(String [] hans){                                 System.out.println("Enter a Sentence :-   ");                                 Scanner hansa = new Scanner(System.in); //initialize Scanner Object                                 String text = hansa.nextLine();  // keyboard inputs ලබා ගනී                                 System.out.println();                                 StringTokenizer tokens=new StringTokenizer(text," ");  // වාක්‍ය කොටස් වලට වෙන් කරයි. text ලෙස පමණක් argument 1 ක් යෙදිය හැක. එවිටද default separator එක වන්නේ space එකයි.                                 while(tokens.hasMoreTokens()){ // tokens තියෙන තරමක් iterate වෙන්න                                                 String tok=tokens.nextToken(); // token එක String variable එකකට                                                 if(tok.startsWith("A")){  //String එක ‘A’ වලින් පටන් ගන්නවද බලනවා                                                 System.out.println(tok);  //එහෙමනම් ඒ String එක print කරනවා                                                 }                                 }                 } }

Question 2 Answers

a.

1. Classes and Object

2. Data Abstraction and Encapsulation

3. Inheritance

4. Polymorphism

5. Interfaces

6. Packages

b.

                1. Eliminate Redundant Code – Inheritance භාවිතය

2. Save time and high productivity – create objects, Reusability

3. Secure programs – Data Abstraction and Encapsulation නිසා

4. Easy upgrading – පොඩි program එක software එකක් වෙනකං

5. Simpler Interfaces – message passing techniques

c.

               

Structured Programming	Object-Oriented Programming
Top-down approach is followed.	Bottom-up approach is followed
Focus is on algorithm and control flow.	Focus is on object model
Program is divided into a number of sub modules, or functions, or procedures.	Program is organized by having a number of classes and objects.
Functions are independent of each other	Each class is related in a hierarchical manner.
No designated receiver in the function call	There is a designated receiver for each message passing
Views data and functions as two separate entities	Views data and function as a single entity
Maintenance is costly	Maintenance is relatively cheaper.
Software reuse is not possible	Helps in software reuse
Function call is used.	Message passing is used
Function abstraction is used	Data abstraction is used.
Algorithm is given importance.	Data is given importance
Solution is solution-domain specific	Solution is problem-domain specific
No encapsulation. Data and functions are separate	Encapsulation packages code and data altogether. Data and functionalities are put together in a single entity.
Relationship between programmer and program is emphasized	Relationship between programmer and user is emphasized.
Data-driven technique is used	Driven by delegation of responsibilities.