Computer Applications — Sample Question Bank

Java Virtual Machine

Reason — JVM stands for Java Virtual Machine, which is responsible for executing Java bytecode and enables Java programs to run on any platform (platform independence).

import java.util.Scanner;

class StepTracker
{
    String name;
    int sw;
    double cb, km;

    public void accept()
    {
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter name: ");
        name = sc.nextLine();
        System.out.print("Enter steps walked: ");
        sw = sc.nextInt();
    }

    public void calculate()
    {
        cb = sw * 0.04;
        km = sw / 1300.0;
    }

    public void display()
    {
        System.out.println("Name: " + name);
        System.out.println("Calories Burned: " + cb);
        System.out.println("Distance (km): " + km);
    }

    public static void main(String args[])
    {
        StepTracker obj = new StepTracker();
        obj.accept();
        obj.calculate();
        obj.display();
    }
}

java.lang

Reason — The Character class methods are found in the java.lang package because this package contains fundamental classes that are automatically available in every Java program. The Character class provides methods to work with characters, such as checking whether a character is a letter, digit, uppercase, or lowercase.

P[1][1]

Reason — In a two-dimensional array P[2][3], the first index represents the row and the second index represents the column. The device "barcode scanner" is located in the second row (index 1) and the second column (index 1), so its index is P[1][1].

Polygon is the class and the pictures are objects

Reason — In object-oriented programming (OOP), a class is a blueprint or template that defines the properties and behaviours (methods) of objects. An object is an instance of a class that holds specific data defined by the class.

In this case:

• Polygon represents the class because it defines the general structure, properties, and methods common to all polygons (e.g., sides, vertices, perimeter calculation).
• The pictures are specific examples or instances of polygons, such as triangles, parallelogram, or pentagons, making them objects created from the Polygon class.

import java.util.Scanner;

public class courier
{
    private String name;
    private double weight;
    private String address;
    private double bill;
    private char type;
    
    public void accept() {
        Scanner in = new Scanner(System.in);

        System.out.print("Enter customer's name: ");
        name = in.nextLine();
        
        System.out.print("Enter recipient's address: ");
        address = in.nextLine();

        System.out.print("Enter parcel weight (in Kgs): ");
        weight = in.nextDouble();

        System.out.println("Enter courier type");
        System.out.print("D (Domestic), I (International): ");
        type = in.next().charAt(0);
    }
    
    public void calculate() {
        if (weight <= 5) {
            bill = weight * 800;
        } else if (weight <= 10) {
            bill = (5 * 800) + ((weight - 5) * 700);
        } else {
            bill = (5 * 800) + (5 * 700) + ((weight - 10) * 500);
        }

        if (type == 'I') {
            bill += 1500;
        }
    }
    
    public void print() {
        System.out.println("Customer's Name: " + name);
        System.out.println("Parcel Weight: " + weight + " Kgs");
        System.out.println("Recipient's Address: " + address);
        System.out.println("Type of Courier: " + type);
        System.out.println("Bill Amount: Rs." + bill);
    }

    public static void main(String[] args) {
        courier obj = new courier();
        obj.accept();
        obj.calculate();
        obj.print();
    }
}

Inheritance

Reason — Inheritance enables new classes to receive or inherit the properties and methods of existing classes.

import java.util.Scanner;

public class Student
{
    private String name;
    private int age;
    private double mks;
    private String stream;
    
    public void accept() 
    {
        Scanner in = new Scanner(System.in);
        System.out.print("Enter student name: ");
        name = in.nextLine();
        System.out.print("Enter age: ");
        age = in.nextInt();
        System.out.print("Enter marks: ");
        mks = in.nextDouble();
    }
    
    public void allocation() 
    {
        if (mks < 75)
            stream = "Try again";
        else if (mks < 200)
            stream = "Arts and Animation";
        else if (mks < 300)
            stream = "Commerce and Computer";
        else
            stream = "Science and Computer";
    }
    
    public void print() 
    {
        System.out.println("Name: " + name);
        System.out.println("Age: " + age);
        System.out.println("Marks: " + mks);
        System.out.println("Stream allocated: " + stream);
    }
    
    public static void main(String args[]) {
        Student obj = new Student();
        obj.accept();
        obj.allocation();
        obj.print();
    }
}

1. Encapsulation
2. Inheritance

(b) Write a difference between unary and binary operator.

unary operators operate on a single operand whereas binary operators operate on two operands.

(c) Name the keyword which:

1. indicates that a method has no return type.
2. makes the variable as a class variable

1. void
2. static

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

1. short — 2 bytes
2. float — 4 bytes

(e) Identify and name the following tokens:

1. public
2. 'a'
3. ==
4. { }

1. Keyword
2. Literal
3. Operator
4. Separator

import java.util.Scanner;

public class ShowRoom
{
    private String name;
    private long mobno;
    private double cost;
    private double dis;
    private double amount;

    public ShowRoom()
    {
        name = "";
        mobno = 0;
        cost = 0.0;
        dis = 0.0;
        amount = 0.0;
    }

    public void input() {
        Scanner in = new Scanner(System.in);
        System.out.print("Enter customer name: ");
        name = in.nextLine();
        System.out.print("Enter customer mobile no: ");
        mobno = in.nextLong();
        System.out.print("Enter cost: ");
        cost = in.nextDouble();
    }
    
    public void calculate() {
        int disPercent = 0;
        if (cost <= 10000)
            disPercent = 5;
        else if (cost <= 20000)
            disPercent = 10;
        else if (cost <= 35000)
            disPercent = 15;
        else
            disPercent = 20;
        
        dis = cost * disPercent / 100.0;
        amount = cost - dis;
    }
    
    public void display() {
        System.out.println("Customer Name: " + name);
        System.out.println("Mobile Number: " + mobno);
        System.out.println("Amout after discount: " + amount);
    }
    
    public static void main(String args[]) {
        ShowRoom obj = new ShowRoom();
        obj.input();
        obj.calculate();
        obj.display();
    }
}