Java Programs - Solved 2007 ICSE Computer Science Paper

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Solved 2007 ICSE Computer Science Paper

Class 10 - ICSE Computer Science Solved Papers

Short Questions/Answers - ICSE 2007 Computer Science

Question 1

a) Name two types of Java programs.
Java Applications and Java Applets.
b) Define instance variable. Give an example of the same.
The variables defined within the class without the static keyword are instance variables. They represent the state of different objects.
Example:
class Square{
double area;
double side;
}
c) Differentiate between binary search and linear search.
Binary search only works on sorted lists, whereas linear search can work on both sorted as well as unsorted lists.
d) Assign the value of pie (i.e. 3.142) to a variable with requisite data type.
double pie = 3.142;
e) Explain with an example the if-else-if construct.
The if-else-if is a conditional construct in which one out of several possible conditions execute.
Example:
if(marks >= 80)
grade = ‘A’;
else if(marks >= 50)
grade = ‘B’
else
grade = ‘C’;

Question 2

a) Differentiate between formal parameter and actual parameter.
The parameters used in method prototype are formal parameters whereas the parameters used in method call are actual parameters.
b) Why do we need a constructor as a class member?
A constructor is used to initialize the data members of an object with legal initial values. It helps in object creation.
c) Explain the term typecasting.
The process of converting the data type of a value from one type to another is known as typecasting.
d) Name the following:
i) A package that is invoked by default.
java.lang
ii) A keyword to use the classes defined in a package.
import
e) Name the class that is used for different mathematical functions. Give an example of a mathematical function.
Math class is used for different mathematical functions. Example: Math.sqrt().

Question 3

a) State the difference between = and ==.
The = is an assignment operator whereas == is a relational operator.
b) Write an equivalent Java syntax for the following expression:

a = (0.05 – 2 * Math.pow(y, 3)) / (x – y);
c) Rewrite the following using ternary operator:
if(income <= 10000)
tax = 0;
else
tax = 12;
tax = (income <= 10000)? 0:12;
d) Write a statement for each of the following:
i) Store a number 275 as a String.
String num = “275”;
ii) Convert a string to a numeric value.
int n = Integer.parseInt(num);
iii) Add it to the existing total of 1000 to update the total.
total = 1000;
total += n;
e) i) What is the role of the keyword void in declaring functions?
The keyword ‘void’ indicates that the method doesn’t return any value.
ii) If a function contains several return statements, how many of them will be executed?
Only one of those return statements is executed.
iii) Which OOP principle implements function overriding?
Inheritance.
f) What is the output of the following?
i) System.out.println(“four: ” + 4 + 2);
System.out.println(“four: ” + (2 + 2));
four: 42
four: 4
ii) String s1 = “Hi”;
String s2 = “Hi”;
String s3 = ” there”;
String s4 = “HI”;
System.out.println(s1 + ” equals ” + s2 + “->” + s1.equals(s2));
System.out.println(s1 + ” equals ” + s3 + “->” + s1.equals(s3));
System.out.println(s1 + ” equals ” + s4 + “->” + s1.equals(s4));
System.out.println(s1 + ” equalsIgnoreCase ” + s4 + “->” + s1.equalsIgnoreCase(s4));
Hi equals Hi -> true
Hi equals there -> false
Hi equals -> false
Hi equalsIgnoreCase HI -> true
g) Evaluate the following expressions, if the values of the variables are a = 2, b = 3 and c = 9.
i) a – (b++) * (–c)
2 – 3 * 10 = 2 – 30 = -28.
ii) a * (++b) % c
2 * 4 % 9 = 8 % 9 = 8.