ICSE 2012 Computer Application Paper Expected Questions - Last Minute Suggestions Part I

Few question and answers are given below. Students can expect these type of questions in ICSE 2012 Computer Application examination.

What do you mean by data encapsulation and polymorphism in Java?

Data encapsulation means hiding the data members of an object using the function members so that the data mebers are prevented from unauthorized access.

Polymorphism is one of the OOP principles by virtue of which different operators or different functions exihibit different behavior while used in different environments. Polymorphism are of three types: Function overloading, function overring and operator overloading.

What is casting, when do we need it? Give an example.

Casting means converting variables or objects from one type to another type. Casting are of two types, automatic or implicit casting and forceful or explicit casting.

Sometimes we work on two variables of same type but the result required is of different type. In such situation casting is needed.

For example, suppose runs scored by a batsman is stored in variable ‘a’ and total innings played by the batsman and total notout are stored in ‘b’ and ‘c’ respectively. Now all these values are of ‘int’ type. We need to calculate the average score of the batsman. If we use the statement like double av=a/(b-c); the result would not be accurate. In this situation explicit casting is needed. Double av=(double)a/(b-c);

Name the package you need to import  for using Scanner class object.

Scanner class is stored in util package which is again under java package.

State the difference between while and do-while loop

While loop is entry control loop while do-while loop is exit control type of loop. In while loop no semicolon is required after the control statement but in do-while loop, semicolon after the control statement is a must.

 State the difference between constructor and function

Constructor is a special function whose name must be same as the class name. Function name must be different from the class name.

Constructor has no return type, not even void while functions maust have a return type.

If constructor is not defined in a class, compiler supplies default constructor. Default constructor means constructor with no argument and empty body. There is no such case with functions.

Explain any two type of access specifiers

There are four type of access specifiers in java and two of them are public and private. The specifiers can be used before class name, variable and function declaration. Public class, function or data member means which can be accessed from anywhere, even from outside the package where the class is defined.

Private data members and function members are only accessible within the class body.

What are the preconditions of binary search?

There are two preconditions of binary search, the first one is that the elements in the list must be in sorted order and the second precondition is about the accessibility of the middle location of list directly. That’s why binary search is applicable only in array.

What is the role of void keyword in declaration of a function

Void keyword in a function specifies that the function will not return any value to the calling program after execution.

Write the name and syntax of the function which is used to extract multiple characters from strings.

‘String substring (int start, int end)’ function of String class is used to extract multiple characters from strings. ‘int start’ denotes the index from where the sub-string will be extracted and ‘int end’ denotes end location of the string upto which the characters will be extracted.

 What is package, give example

 Package are containers of classes, abstract classes and interfaces. Package may contain packages also but ultimately they contain classes, abstract classes and interfaces. Example of packages are ‘lang’ package, ‘io’ package etc.

Find the output of the following code segments:

int a=0,b=0;

for(a=0;a<=5;a+=2)

for(b=0;b<=a;++b)

System.out.println(“Answer1:”+(++a)+b++);

System.out.println(“Answer2:”+(++a)+b++);

Output:

Answer1:10

Answer1:30

Answer1:42

Answer1:54

Answer2:76

 Output of the following code segment:

int I,j,arr[]=new int[7];

arr[0]=1;

for(i=0;i<6;i++)

{

for(j=i+1;j>0;j--)

arr[j]=arr[j]+arr[j-1];

System.out.println();

}

 Output: Six blank lines

Following program segment is to print the the sum of the prime digits of an entered number:

For example, if entered number is 1872, the output will be – sum of the prime digitd is 9 ( as 7 and 2 are two prime digits in 1872)

int digit,sum=0,n=1872;

while(n>0)

{

 ?1?=n%10;

If(digit==2||?2?||?3?||digit==7)

sum=?4?;

n=n/10;

}

System.out.println(“Sum of prime digits is”+sum);

Fill up the statements marked with question mark.

?1?: digit

?2?: digit==3

?3?: digit==5

?4?: sum+digit

  

What is private visibility of a method

Private function means which can not be accessed from outside the class body. Private functions can be invoked by other functions defined in a class only.

 Explain function overloading with example

Function overloading means where function names must be same and argument list of the functions should be different. The return type of the functions can be same or different. Function overloading is possible in same class as well as in sub classes.

void change ()

{

 System.out.println(“Nothing to change…”);

}

void change ( int a, int b)

{

a=a+b;

b=a-b;

a=a-b;

System.out.println(“Values changed =” + a + “,”+b);

}

What does System.in and System.out refers to

System.in is inbuilt input object where the terminal input value is stored in byte. System.out is the inbuilt output object whose functions like println () and print () are used for terminal output.

What is exit control loop? Give example

Exit control loop is that type of loop where body of the loop appears before the control statement of the loop. Do or do-while loop is an example of exit control loop. In such type of loop, loop body execution for at least once is confirmed as the control enters the loop body in the first iteration with out checking any condition.

What is recursive function, give example

Recursive functions are those specific functions where the function is called repetadely from a state,ment used within the body of the function itself. A base value is needed in recursive function to stop the calling.

Write a statement to import a class ‘Nano’ under the package ‘Car’ which is again under the package ‘Tata’ and Tata is under ‘Indian’ package

import Indian.Tata.Car.Nano;

What will be the output of the following program segment?

String name[]={“Computer”,”Application”};

System.out.println(name[0].length());

System.out.println(name.length);

 First output: 8 as length of Computer is 8.

Second output is 2 as there are two elements in the array name.

 Give the output:

class Outt

{

 public void av()

{

 for(i=0;i<=10;i++)

{

If(i==6)

Break;

}

System.out.println(i);

}

}

  

Output: 6

Give the output:

TuTOrIaI”.indexOf(‘I’);

Math.rint(-38.96);

Math.abs(4789.45);

Math.max(Math.min(15,25),5);

(int)(“Scholar”.charAt(2));

Math.ceil(-28.25);

“MISSISSIPPI”.lastIndexOf(‘S’);

Math.floor(-524.99);

“suddhashil”.substring(3,4);

Math.sqrt(100);

Output:

5

-39.0

4789.45

15

104

-28.0

6

-525.0

d

10.0

Another set of suggestions for ICSE 2012 Computer Application will be posted very soon.