ICSE Class 10 Computer Applications Board Exam Question Paper 2019 with Solutions

ICSE Class 10 Computer Applications Board Exam Question Paper with Solutions

SECTION A [40 Marks]

Question 1. [10 Marks]

(a) Name any two basic principles of Object-oriented Programming. [2 Marks]

Answer:
Abstraction and Encapsulation.

Teacher's Note:
a) Abstraction refers to hiding internal implementation details, while encapsulation binds data and methods together.
b) Students must remember that polymorphism and inheritance are also core principles, but any two valid principles suffice.

(b) Write a difference between unary and binary operator. [2 Marks]

Answer:

Teacher's Note:
a) Unary operators operate on a single variable or value.
b) Binary operators combine two operands to yield a single result.

(c) Name the keyword which : [2 Marks]
(i) indicates that a method has no return type.
(ii) makes the variable as a class variable.

Answer:
(i) void
(ii) static

Teacher's Note:
a) The keyword void specifies that a method does not return any value to the calling code.
b) The keyword static ensures that the variable belongs to the class rather than to any specific instance (object).

(d) Write the memory capacity (storage size) of short and float data type in bytes. [2 Marks]

Answer:
(i) short: 2 bytes
(ii) float: 4 bytes

Teacher's Note:
a) The short data type is a 16-bit signed integer.
b) The float data type is a 32-bit single-precision floating-point number.

(e) Identify and name the following tokens : [2 Marks]
(i) public
(ii) ‘a’
(iii) ==
(iv) {}

Answer:
(i) Keyword
(ii) Literal (Character literal)
(iii) Operator (Relational operator)
(iv) Separator

Teacher's Note:
a) Tokens are the smallest individual units of a Java program.
b) Keywords are reserved words with predefined meanings, whereas delimiters or separators like braces mark the boundaries of code blocks.

Question 2. [10 Marks]

(a) Differentiate between if else if and switch-case statements. [2 Marks]

Answer:

Teacher's Note:
a) Use if-else-if when dealing with complex boolean conditions.
b) Use switch-case for multi-way branching against discrete constant values.

(b) Give the output of the following code : [2 Marks]
String P = "20", Q = "19";
int a = Integer.parseInt(P);
int b = Integer.valueOf(Q);
System.out.println(a+""+b);

Answer:
2019

Teacher's Note:
a) Integer.parseInt() and Integer.valueOf() convert the string representations into integer values 20 and 19 respectively.
b) The expression a + "" + b performs string concatenation, resulting in the combined string "2019".

(c) What are the various types of errors in Java ? [2 Marks]

Answer:
1. Syntax errors
2. Runtime errors
3. Logical errors

Teacher's Note:
a) Syntax errors are caught by the compiler due to violations of programming rules.
b) Runtime errors occur during program execution (such as division by zero), while logical errors produce incorrect output due to flawed algorithm design.

(d) State the data type and value of res after the following is executed : [2 Marks]
char ch = '9';
res = Character.isDigit(ch);

Answer:
Data type: boolean
Value: true

Teacher's Note:
a) The method Character.isDigit() checks whether the specified character is a digit.
b) Since '9' is a numeric character, the method returns the boolean value true.

(e) What is the difference between the linear search and the binary search technique? [2 Marks]

Answer:

Teacher's Note:
a) Linear search has a time complexity of O(n), making it slower for large datasets.
b) Binary search has a time complexity of O(log n), making it much faster for sorted datasets.

Question 3. [20 Marks]

(a) Write a Java expression for the following : [2 Marks]
\( |x^{2}+2xy| \)

Answer:
Math.abs((x * x) + (2 * x * y));

Teacher's Note:
a) Math.abs() is used to compute the absolute value representing the mathematical modulus operation.
b) Explicit multiplication operators (*) must be included between variables in Java expressions.

(b) Write the return data type of the following functions : [2 Marks]
(i) startsWith( )
(ii) random( )

Answer:
(i) boolean
(ii) double

Teacher's Note:
a) startsWith() checks string prefixes and returns true or false.
b) Math.random() returns a pseudo-random double value greater than or equal to 0.0 and less than 1.0.

(c) If the value of basic = 1500, what will be the value of tax after the following statement is executed? [2 Marks]
tax = basic > 1200 ? 200 : 100;

Answer:
tax = 200

Teacher's Note:
a) The conditional operator evaluates the condition basic > 1200.
b) Since 1500 is greater than 1200, the expression evaluates to the first value, which is 200.

(d) Give the output of following code and mention how many times the loop will execute ? [2 Marks]
int i;
for(i = 5; i >= 1; i--)
{
    if(i % 2 == 1)
    continue;
    System.out.print(i + " ");
}

Answer:
Output: 4 2
Loop will execute 5 times.

Teacher's Note:
a) The loop iterates for i = 5, 4, 3, 2, 1 (total 5 iterations).
b) When i is odd (5, 3, 1), the continue statement skips printing, so only even numbers (4, 2) are printed.

(e) State a difference between call by value and call by reference. [2 Marks]

Answer:

Teacher's Note:
a) Primitive data types in Java are passed by value.
b) Reference types such as objects and arrays are passed by reference (referencing the same memory location).

(f) Give the output of the following: [2 Marks]
Math.sqrt(Math.max(9, 16))

Answer:
4.0

Teacher's Note:
a) Math.max(9, 16) evaluates to 16.
b) Math.sqrt(16) returns the double value 4.0.

(g) Write the output for the following: [2 Marks]
String s1 = "phoenix";
String s2 = "island";
System.out.println(s1.substring(0).concat(s2.substring(2)));
System.out.println(s2.toUpperCase());

Answer:
phoenixland
ISLAND

Teacher's Note:
a) s1.substring(0) is "phoenix" and s2.substring(2) is "land"; concatenating them gives "phoenixland".
b) s2.toUpperCase() converts "island" to uppercase letters "ISLAND".

(h) Evaluate the following expression if the value of x=2, y=3 and z=1. [2 Marks]
v = x + --z + y++ + +y

Answer:
v = 10

Teacher's Note:
a) Step-by-step evaluation with x = 2, y = 3, z = 1: --z decrements z to 0 and uses 0. Then y++ uses 3 and increments y to 4. The unary plus +y uses the updated y (4).
b) Thus, v = 2 + 0 + 3 + 4 = 9.

(i) String x[ ] = {"Artificial intelligence", "IOT", "Machine learning", "Big data"};
Give the output of the following statements: [2 Marks]
(i) System.out.println(x[3]);
(ii) System.out.println(x.length);

Answer:
(i) Big data
(ii) 4

Teacher's Note:
a) Array indexing in Java starts from 0, so x[3] refers to the fourth element, "Big data".
b) The length field returns the total number of elements in the array, which is 4.

(j) What is meant by a package? Give an example. [2 Marks]

Answer:
A package is an organized collection of classes and interfaces grouped together to protect name spaces and prevent naming conflicts. For example, the java.util package contains utility classes like Scanner and Random.

Teacher's Note:
a) Packages help in modularizing code and controlling access protection.
b) Built-in packages can be imported into programs using the import statement.

SECTION B [60 Marks]
Attempt any four questions from this Section

Question 4. [15 Marks]
Design a class name ShowRoom with the following description :
Instance variables/ Data members :
String name - To store the name of the customer
long mobno - To store the mobile number of the customer
double cost - To store the cost of the items purchased
double dis - To store the discount amount
double amount - To store the amount to be paid after discount
Member methods: -
ShowRoom() - default constructor to initialize data members
void input() - To input customer name, mobile number, cost
void calculate() - To calculate discount on the cost of purchased items, based on following criteria
Cost Discount (in percentage)
Less than or equal to Rs. 10000 : 5%
More than Rs. 10000 and less than or equal to Rs. 20000 : 10%
More than Rs. 20000 and less than or equal to Rs. 35000 : 15%
More than Rs. 35000 : 20%
void display() - To display customer name, mobile number, amount to be paid after discount
Write a main method to create an object of the class and call the above member methods.

Answer:
import java.util.*;
class ShowRoom {
    String name;
    long mobno;
    double cost;
    double dis;
    double amount;
    ShowRoom() {
        name = "";
        mobno = 0;
        cost = 0.0;
        dis = 0.0;
        amount = 0.0;
    }
    void input() {
        Scanner sc = new Scanner(System.in);
        System.out.println("Enter Name:");
        name = sc.nextLine();
        System.out.println("Enter Mobile number:");
        mobno = sc.nextLong();
        System.out.println("Enter cost:");
        cost = sc.nextDouble();
    }
    void calculate() {
        if (cost <= 10000) {
            dis = cost * 5 / 100;
        }
        else if (cost > 10000 && cost <= 20000) {
            dis = cost * 10 / 100;
        }
        else if (cost > 20000 && cost <= 35000) {
            dis = cost * 15 / 100;
        }
        else {
            dis = cost * 20 / 100;
        }
        amount = cost - dis;
    }
    void display() {
        System.out.println("Name: " + name);
        System.out.println("Mobile No.: " + mobno);
        System.out.println("Amount: " + amount);
    }
    public static void main(String args[]) {
        ShowRoom ob = new ShowRoom();
        ob.input();
        ob.calculate();
        ob.display();
    }
}

Teacher's Note:
a) Ensure all instance variables are properly initialized inside the default constructor.
b) The discount slab logic uses chained if-else statements to assign the correct percentage based on cost limits.

Question 5. [15 Marks]
Using the switch-case statement, write a menu driven program to do the following :
(a) To generate and print Letters from A to Z and their Unicode
(b) Display the following pattern using iteration (looping) statement:
1
1 2
1 2 3
1 2 3 4
1 2 3 4 5

Answer:
import java.util.*;
class SwitchCase {
    public static void main(String args[]) {
        Scanner sc = new Scanner(System.in);
        System.out.println("1. Enter 1 for Unicode");
        System.out.println("2. Enter 2 for Pattern");
        System.out.println("Enter your choice:");
        int choice = sc.nextInt();
        switch(choice) {
            case 1:
                char ch;
                System.out.println("Letters \t Unicode");
                for (ch = 'A'; ch <= 'Z'; ch++) {
                    System.out.println(ch + "\t" + (int)ch);
                }
                break;
            case 2:
                int i, j;
                for (i = 1; i <= 5; i++) {
                    for (j = 1; j <= i; j++) {
                        System.out.print(j + " ");
                    }
                    System.out.println();
                }
                break;
            default:
                System.out.println("Wrong choice entered.");
        }
    }
}

Teacher's Note:
a) A menu-driven program requires a switch statement with clear case blocks and a default handler.
b) Explicit casting to (int) prints the Unicode value of character variables in case 1.

Question 6. [15 Marks]
Write a program to input 15 integer elements in an array and sort them in ascending order using the bubble sort technique.

Answer:
import java.util.*;
class AscendingOrder {
    public static void main(String args[]) {
        int i, j, temp;
        Scanner sc = new Scanner(System.in);
        int arr[] = new int[15];
        System.out.println("Enter 15 integers:");
        for (i = 0; i < 15; i++) {
            arr[i] = sc.nextInt();
        }
        for (i = 0; i < 14; i++) {
            for (j = 0; j < 14 - i; j++) {
                if (arr[j] > arr[j + 1]) {
                    temp = arr[j];
                    arr[j] = arr[j + 1];
                    arr[j + 1] = temp;
                }
            }
        }
        System.out.println("Elements in ascending order are:");
        for (i = 0; i < 15; i++) {
            System.out.println(arr[i]);
        }
    }
}

Teacher's Note:
a) Bubble sort repeatedly compares adjacent elements and swaps them if they are in the wrong order.
b) The inner loop boundary 14 - i optimizes performance by ignoring already sorted elements at the end.

Question 7. [15 Marks]
Design a class to overload a function series() as follows :
(a) void series (int x, int n) - To display the sum of the series given below:
\( x^{1} + x^{2} + x^{3} + \dots + x^{n} \) terms
(b) void series (int p) - To display the following series:
0, 7, 26, 63 \dots p terms.
(c) void series () - To display the sum of the series given below:
\( \frac{1}{2} + \frac{1}{3} + \frac{1}{4} + \dots + \frac{1}{10} \)

Answer:
class OverloadSeries {
    void series(int x, int n) {
        int i;
        double sum = 0;
        for (i = 1; i <= n; i++) {
            sum = sum + Math.pow(x, i);
        }
        System.out.println("Sum: " + sum);
    }
    void series(int p) {
        int i;
        for (i = 1; i <= p; i++) {
            System.out.print((i * i * i) - 1 + " ");
        }
        System.out.println();
    }
    void series() {
        double i;
        double s = 0;
        for (i = 2; i <= 10; i++) {
            s = s + 1 / i;
        }
        System.out.println("Sum: " + s);
    }
}

Teacher's Note:
a) Function overloading requires methods to share the same name within the same class but have different parameter lists.
b) For the third method, starting the loop counter at 2 ensures fractional terms from 1/2 up to 1/10.

Question 8. [15 Marks]
Write a program to input a sentence and convert it into uppercase and count and display the total number of words starting with a letter 'A'.
Example:
Sample Input: ADVANCEMENT AND APPLICATION OF INFORMATION TECHNOLOGY ARE EVER CHANGING.
Sample Output : Total number of words starting with letter 'A' = 4.

Answer:
import java.util.*;
class UpperCount {
    public static void main(String args[]) {
        int i, count = 0;
        Scanner sc = new Scanner(System.in);
        System.out.println("Enter sentence:");
        String str = sc.nextLine();
        str = str.toUpperCase();
        str = " " + str;
        for (i = 0; i < str.length() - 1; i++) {
            if (str.charAt(i) == ' ' && str.charAt(i + 1) == 'A') {
                count++;
            }
        }
        System.out.println("Total number of words starting with letter 'A' = " + count);
    }
}

Teacher's Note:
a) Prepending a space to the sentence simplifies word boundary checks for the first word.
b) Checking if a character is a space followed by 'A' accurately counts words starting with 'A'.

Question 9. [15 Marks]
A tech number has even number of digits. If the number is split in two equal halves, then the square of sum of these halves is equal to the number itself. Write a program to generate and print all four digit tech numbers.
Example :
Consider the number 3025
Square of sum of the halves of 3025 = (30+25)² = (55)² = 3025 is a tech number.

Answer:
class TechNumber {
    public static void main(String args[]) {
        int i, a, b, sum;
        String n;
        System.out.println("Four Digit Tech Numbers are:");
        for (i = 1000; i <= 9999; i++) {
            n = i + "";
            a = Integer.parseInt(n.substring(0, 2));
            b = Integer.parseInt(n.substring(2));
            sum = (int)Math.pow((a + b), 2);
            if (sum == i) {
                System.out.println(i);
            }
        }
    }
}

Teacher's Note:
a) The loop iterates through all four-digit numbers from 1000 to 9999.
b) Substring extraction splits the number into two equal halves of 2 digits each for the condition check.