ICSE Class 10 Sample Paper 2021-2022 Answer sheet

COMPUTER APPLICATIONS
 (Theory)
(Two hours)

Answers to this Paper must be written on the paper provided separately.
You will not be allowed to write during the first 15 minutes.
This time is to be spent in reading the question paper.
The time given at the head of this Paper is the time allowed for writing the answers. 

This Paper is divided into two Sections.
Attempt all questions from Section A and any four questions from Section B.
The intended marks for questions or parts of questions are given in brackets [ ].

SECTION A (40 Marks)
Attempt all questions(2 marks each question)

Question 1.

a . What do mean by Inheritance and Polymorphism in Java?
Ans. Inheritance

• When one object acquires the properties and behaviors of a parent object, it is known as inheritance. The data and methods available to the parent class or super class is also available to the child class with the same names.
• It also provides code reusability.
• For e.g. we can have a class shape from which I can drive sub class Circle, Triangle, Square etc…

Polymorphism

• Polymorphism means having many forms. In Java, we use method overloading and method overriding to achieve polymorphism.
• In method overloading, we can have multiple methods with same name, like to find area, based upon number of parameters the function can work for different shapes.
• In case of inheritance, the derived class can either use the method of base class or it can have its own implementation of the method which will then override the base class function. This is called method overriding.

• Polymorphism simplifies usage of object methods by external code and Java takes care of calling the right method with the help of the signature and declaration of these entities

b . Give the output of this code

int a = 9; a++;
System.out.println (a);
a -= a-- - --a;
System  .out.println (a);

Ans:  10
            8         
       Explanation

            a = 9;
            a++;                 // a = 10
           SOP (a)            // Prints 10
                   a -= a– – –a;
                   a = 10 – (10 – 8)
                   a = 10 -2 = 8
                  SOP (a)            // Prints 8                    

c . What is the value stored in x and y after execution of these statements?

             double x = Math.ceil(8.3) + Math.floor(-3.2)+Math.rint(4.5);
             double y = Math.abs(Math.round(Math.max( -4.4, -9.6)));  
Ans.

X = 9.0       Working: 9.0 + (-4.0) + 4.0 = 9.0
Y = 4.0       Working    Math.abs(Math.round(-4.4)) = 4.0

d . Give the total number of bytes occupied by these arrays?

1. 1. int ar[25]
   2. double A[12]

Ans. The number of bytes:

1. 1. ar[25] = 4*25                 =100 bytes.
   2. A[12] = 8*12                  =96 bytes

e . What is the output of this code? Show the working

long num=729, sum 0;
for( long y= num; y> 0; y= y/10){
      sum= sum + y % 10;
}
System.out.println("Sum of digits = "+ sum);

 Ans. Sum of digits = 18

                          Initialization   num = 729, sum = 0, y = 729
                          Iteration 1: sum = 0 + 729 % 10 = 9
                          Iteration 2:     y = 729/10 = 72
                                                sum = 9 + 72%10 = 11
                          Iteration 3      y = 72/10 = 7
                                                sum = 11 + 7%10 = 18
                                                y = 7/10 = 0 so the loop exits.
                          Print: Sum of digits = 18

Question 2.

a . If int y = 10 then find int z = (++y * (y++ + 5));
Ans. Increment operator has the highest precedence. So, ++y and y++ will be evaluated starting from left.
In ++y, the value of y will be incremented to 11 and then 11 will be used in the expression. When y++ is evaluated, the current value of y i.e. 11 will be used and then y will be incremented from 11 to 12.
             int z = (++y * (y++ + 5));
                      = 11 * (11 + 5 )
                      = 11 * 16
                      = 176

b . State the result of the following statement.

System.out.print(“My Friends are \n”);
System.out.print(“Ronit \tNihir \t”);
System.out.print(“and Ananya too”); 

Ans.

My Friends are
Ronit      Nihir     and Ananya too.

c . What do you mean by function overloading? Explain with the help of one example.    
Ans. Java allows creating or defining various functions/methods by the same name which are differentiated by their data types or number of arguments. This is known as function overloading.
Example

class Overloading{
      int Sum(int a){      // 1st overloaded function with one argument
            return a*a;
      }
      int Sum(int a, int b){     // 2nd overloaded function with two arguments
            return ((a*a) + (b*b));
      }
}

d . What is the output of the following statements when executed?
          char ch[ ]= {‘I’, ‘N’, T’, E’, ‘L’, P’, ‘E’, ‘N’, ‘T’, ‘I’, ‘U’, ‘M’};
         String obj= new String(ch, 3, 4);
         System.out.println(“The result is = “+ obj

Ans:
Output: ELPE

e . Differentiate between Character.toLowerCase() and Character.toUpperCase() methods. With an example.      

Question 3.     

a . Explain the statements (i) and (ii) from the following code.

char x =’a’;
(i) x+= 3;    // why will this run?
(ii) x= x +3;  //why will this gives compile time error?       

Ans.

(i) Because x += 3; is equivalent to x = (char) (x+3); // here (char) is type casting
(ii) Where x +3 is default to int operation, assign an int to char must be type cast.

b . State the method that: 
           i. Converts a string to a primitive float data type
          ii. Determines if the specified character is an uppercase character
Ans.
           i. Float.parseFloat()
          ii. Character.isUpperCase()

c . What is the difference between pure and impure function?   

d . What is this keyword? Also discuss the significance 
Ans. Keyword THIS is a reference variable in Java that refers to the current object. It is   automatically created when an object is created.
It can be used -:

• To refer to instance variable of current class
• To invoke or initiate current class
• To return the current class instance
• To pass as argument to class method or constructor.
  e.g

Class Simply {
    int x, y;
    // Constructor
    Simply (int x, int y)
    {
         this.x = x;
         this.y = y;
    }
}

e . State the output of this program Segment?

String str1 = ”great”;
String str2= “Minds”;
System.out.println(str1.substring(0,2). Concat(str2.substring(1)));
System.out.println(( “WH”+(str1.substring(2).toUpperCase() ))); 

Ans.

The 1^st output is= grinds   ( because str1. Substring(0,2)gives “gr” & str2. Substring(1) gives “inds”)
The 2^nd output is= WHEAT  ( because str1. Substring(2). toUpperCase() gives “EAT”, so  ”WH”+”EAT”= “WHEAT”)

f . Write a statement each to perform the following task on a string:

1. 1. Extract the second last character of a word stored in the variable wd.
   2. Cheek if the second character of a string str is in uppercase.

Ans.

1. 1. char ch = wd.charAt(wt.length() -2);
   2. if (Character.isUpperCase(str.charAt(1)))          OR
      if (str.charAt(1)> ‘A ‘ && str.charAt(1) <= ‘z’)

g . Find the errors in the given program segment and re-write the statements correctly to assign values to an integer array.

int a= new int(5);
for(int i=0; i<=5; i++)
    a[i]= I; 

Ans. The statement 1 has two errors: the square brackets ‘[ ]’ is required as “int[ ] a” or “int a[ ]”. Also, the size of the array 5 should be within the ‘[ ]’ bracket instead of ( ).

The statement 2 has one error. The loop should be 0 to 4 i.e. for( int i=0; i< 5; i++) or for( int i= 0; i <5;i++)

Correct program code

int a[ ]= new int[ 5 ];
for(int i= 0; i <5; i++)
    a[i]= i;;

h . What do you mean by Punctuators? Give examples.   
Ans. The specific symbols used to indicate how group of codes are divided and arranged are known as punctuators.
Examples:

[ ] (used for creating array),
{} (used to make compound statement body),
() (used to perform arithmetic operations, used to enclose arguments of the function, for type casting),
; (semicolon- used as statement terminator),
, (comma- used to separate list of variables),
. (dot or decimal- used make fraction value, include package, referencing object).

i . If String n1 = “99”; and String n2=”100”; Give the output of the following:

1. 1. String st= n1+n2; System.out.println (st) ;
   2. System.out.println( n1.charAt( 1 ));
   3. System.out.println( n2 + n1);
   4. System.out.printlnt (n1+ “ ”+n2); [2]

 Ans.

1. 1. 99100
   2. 9
   3. 10099
   4. 99 100

j . Write an expression for :