ICSE Class 10 Computer Applications Board Exam Question Paper 2011 with Solutions

ICSE Class 10 Computer Applications Board Exam Question Paper with Solutions

SECTION - A (40 MARKS)

(Attempt all questions)

Question 1.

(a) What is the difference between an object and a class? [2 Marks]

Answer:
1. A class is a user-defined blueprint or prototype from which objects are created, whereas an object is a basic unit of Object Oriented Programming and is an instance of a class.
2. A class does not take up any space in memory when declared, whereas an object occupies physical memory when it is created using the new operator.

Teacher's Note:
a) Emphasize that a class is a logical entity while an object is a physical or runtime entity.
b) Avoid confusing them; remember the golden rule: class is the template, object is the realization.

(b) What does the token 'keyword' refer to, in the context of Java? Give an example for keyword. [2 Marks]

Answer:
1. Keywords are reserved words that have predefined meaning to the Java compiler and cannot be used as identifiers (variable names, class names, etc.).
2. Example: int, class, public, void, etc. (Any one)

Teacher's Note:
a) Keywords are always written in lowercase in Java.
b) Students often lose marks by writing user-defined words like sum or main as examples of keywords.

(c) State the difference between entry controlled loop and exit controlled loop. [2 Marks]

Answer:
1. In an entry-controlled loop, the condition is tested before entering the loop body (e.g., for, while), so the body may not execute at all if the condition is false initially.
2. In an exit-controlled loop, the condition is checked at the end of the loop body (e.g., do-while), ensuring the loop body executes at least once.

Teacher's Note:
a) Clearly mention the specific loop constructs as examples for each type.
b) Point out that do-while requires a semicolon at the end of the while condition.

(d) What are the two ways of invoking functions? [2 Marks]

Answer:
The two ways of invoking functions (methods) are:
1. Call by Value (passing the value of arguments to the method parameter).
2. Call by Reference (passing the reference or address of objects to the method).

Teacher's Note:
a) Java strictly supports call by value for primitive data types.
b) Be precise with technical terms like formal and actual parameters when explaining function invocation.

(e) What is the difference between / and % operator? [2 Marks]

Answer:
1. The division operator (/) returns the quotient of the division operation.
2. The modulus operator (%) returns the remainder of the division operation.

Teacher's Note:
a) Both can be used with integer and floating-point types in Java.
b) Students often mix up / and %, especially when extracting individual digits from a number.

Question 2.

(a) State the total size in bytes, of the arrays a[4] of char data type and p[4] of float data type. [2 Marks]

Answer:
1. Size of char array a[4] = 4 × 2 bytes = 8 bytes (since a char in Java occupies 2 bytes).
2. Size of float array p[4] = 4 × 4 bytes = 16 bytes (since a float in Java occupies 4 bytes).

Teacher's Note:
a) Remember that Java uses Unicode for characters, making char 2 bytes, unlike C/C++ where it is 1 byte.
b) Always multiply the array size by the exact byte size of the primitive data type.

(b) (i) Name the package that contains Scanner class.
(ii) Which unit of the class gets called, when the object of the class is created? [2 Marks]

Answer:
(i) java.util
(ii) Constructor

Teacher's Note:
a) Remind students to write the package name correctly with proper capitalization (java.util).
b) A constructor has the same name as the class and does not have any return type.

(c) Give the output of the following:
String n = "Computer Knowledge";
String m = "Computer Applications";
System.out.println(n.substring(0,8).concat(m.substring(9)));
System.out.println(n.endsWith("e")); [2 Marks]

Answer:
ComputerApplications
true

Teacher's Note:
a) n.substring(0,8) extracts "Computer", and m.substring(9) extracts "Applications".
b) concat joins them without a space, resulting in "ComputerApplications".

(d) Write the output of the following:
(i) System.out.println(Character.isUpperCase('R'));
(ii) System.out.println(Character.toUpperCase('j')); [2 Marks]

Answer:
(i) true
(ii) J

Teacher's Note:
a) Character class methods are static and called using the class name.
b) Notice the return type of isUpperCase is boolean (true/false) and toUpperCase is char.

(e) What is the role of keyword void in declaring functions? [2 Marks]

Answer:
The void keyword specifies that a method does not return any value to the calling code.

Teacher's Note:
a) Methods with void return type cannot use the return statement with a value.
b) It is commonly used for procedures or display methods.

Question 3.

(a) Analyse the following program segment and determine how many times the loop will be executed and what will be the output of the program segment?
int p = 200;
while(true)
{
    if(p<100)
        break;
    p = p - 20;
}
System.out.println(p); [2 Marks]

Answer:
Loop execution count: 6 times.
Output: 80

Teacher's Note:
a) Trace carefully: p starts at 200, decreases by 20 each iteration (200, 180, 160, 140, 120, 100, 80).
b) When p becomes 80, the condition p < 100 becomes true, executing the break statement.

(b) What will be the output of the following code?
(i) int k=5, j=9;
    k+=k++ - ++j + k;
    System.out.println("k="+k);
    System.out.println("j="+j);
(ii) double b = -15.6;
    double a = Math.rint(Math.abs(b));
    System.out.println("a="+a); [2 Marks]

Answer:
(i) k=10
    j=10
(ii) a=16.0

Teacher's Note:
a) In part (i), evaluate step-by-step considering operator precedence and pre/post increment operators.
b) In part (ii), Math.abs(-15.6) gives 15.6, and Math.rint(15.6) rounds to the nearest integer as a double, which is 16.0.

(c) Explain the concept of constructor overloading with an example. [2 Marks]

Answer:
1. Constructor overloading is the process of having more than one constructor in a class with the same name (class name) but differing in the number, sequence, or types of parameters.
2. Example:
    class Sample {
        Sample() { } // Default constructor
        Sample(int x) { } // Parameterized constructor
    }

Teacher's Note:
a) It is a form of compile-time polymorphism.
b) Ensure the parameter list must be distinct for each overloaded constructor.

(d) Give the prototype of a function search which receives a sentence sentnc and a word wrd and returns 1 or 0? [2 Marks]

Answer:
int search(String sentnc, String wrd)

Teacher's Note:
a) The return type must be int because it returns 1 or 0.
b) Check parameter names and types as requested in the question.

(e) Write an expression in Java for z = \(\frac{5x^3 + 2y}{x + y}\) [2 Marks]

Answer:
double z = (5 * Math.pow(x, 3) + 2 * y) / (x + y);

Teacher's Note:
a) Always use Math.pow(x, 3) for exponents in Java.
b) Enclose numerator and denominator in parentheses to ensure correct evaluation order.

(f) Write a statement each to perform the following task on a string:
(i) Find and display the position of the last space in a string s.
(ii) Convert a number stored in a string variable x to double data type. [2 Marks]

Answer:
(i) System.out.println(s.lastIndexOf(' '));
(ii) double d = Double.parseDouble(x);

Teacher's Note:
a) lastIndexOf returns the index of the last occurrence of the specified character.
b) Double.parseDouble() is the standard parsing method for converting a String to a double.

(g) Name the keyword that
(i) informs that an error has occurred in an input/output operation.
(ii) distinguishes between instance variables and class variables. [2 Marks]

Answer:
(i) throws (or try / catch / throw)
(ii) static

Teacher's Note:
a) IOException is signaled using throws in method signatures for I/O operations.
b) The static keyword defines class variables shared across all instances.

(h) What are library classes? Give an example. [2 Marks]

Answer:
1. Library classes are pre-written classes provided by Java (part of the Java API) that are grouped into packages and ready to be imported and used.
2. Example: Scanner, Math, String, etc. (Any one)

Teacher's Note:
a) They save development time by providing pre-built functionalities.
b) Distinguish them from user-defined classes created by programmers.

(i) Write one difference between Linear Search and Binary Search. [2 Marks]

Answer:
Linear search can be performed on both sorted and unsorted arrays, whereas binary search requires the array to be sorted in a specific order before searching.

Teacher's Note:
a) Binary search is much faster (logarithmic time complexity) compared to linear search (linear time complexity).
b) Emphasize the prerequisite of sorting for binary search.

SECTION - B (60 MARKS)

Attempt any four questions from this Section.
The answers in this Section should consist of the Programs in either BlueJ environment or any program environment with Java as the base.
Each program should be written using Variable descriptions/Mnemonic Codes such that the logic of the program is clearly depicted.
Flow-Charts and Algorithms are not required.

Question 4. [15 Marks]
Define a class called mobike with the following description :
Instance variables / data members :
int bno - to store the bike's number
int phno - to store the phone number of the customer
String name - to store the name of the customer
int days - to store the number of days the bike is taken on rent
int charge - to calculate and store the rental charge
Member methods :
void input() - to input and store the detail of the customer
void compute() - to compute the rental charge.
The rent for a mobike is charged on the following basis :
First five days Rs. 500 per day.
Next five days Rs. 400 per day.
Rest of the days Rs. 200 per day.
void display() - to display the details in the following format :
Bike No. Phone No. Name No. of days Charge

Answer:

import java.util.Scanner;
public class mobike {
    int bno, phno, days, charge;
    String name;
    
    void input() {
        Scanner sc = new Scanner(System.in);
        System.out.println("Enter Bike Number:");
        bno = sc.nextInt();
        System.out.println("Enter Phone Number:");
        phno = sc.nextInt();
        System.out.println("Enter Customer Name:");
        sc.nextLine();
        name = sc.nextLine();
        System.out.println("Enter Number of Days:");
        days = sc.nextInt();
    }
    
    void compute() {
        if (days <= 5) {
            charge = days * 500;
        }
        else if (days <= 10) {
            charge = (5 * 500) + (days - 5) * 400;
        }
        else {
            charge = (5 * 500) + (5 * 400) + (days - 10) * 200;
        }
    }
    
    void display() {
        System.out.println("Bike No.\tPhone No.\tName\tNo. of days\tCharge");
        System.out.println(bno + "\t\t" + phno + "\t\t" + name + "\t" + days + "\t\t" + charge);
    }
    
    public static void main(String[] args) {
        mobike ob = new mobike();
        ob.input();
        ob.compute();
        ob.display();
    }
}

Teacher's Note:
a) Ensure all requested data members and methods are implemented with correct access and return types.
b) Verify slab calculations carefully: first 5 days at 500, next 5 days (days 6-10) at 400, and remaining days at 200.

Question 5. [15 Marks]
Write a program to input and store the weight of ten people. Sort and display them in descending order using the selection sort technique.

Answer:

import java.util.Scanner;
public class SortWeight {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        double[] w = new double[10];
        System.out.println("Enter weight of 10 people:");
        for (int i = 0; i < 10; i++) {
            w[i] = sc.nextDouble();
        }
        
        // Selection Sort for descending order
        for (int i = 0; i < 9; i++) {
            int maxIdx = i;
            for (int j = i + 1; j < 10; j++) {
                if (w[j] > w[maxIdx]) {
                    maxIdx = j;
                }
            }
            double temp = w[i];
            w[i] = w[maxIdx];
            w[maxIdx] = temp;
        }
        
        System.out.println("Weights in descending order:");
        for (int i = 0; i < 10; i++) {
            System.out.println(w[i]);
        }
    }
}

Teacher's Note:
a) Selection sort requires finding the maximum (for descending order) or minimum (for ascending order) element in each pass.
b) Array size is fixed at 10 as specified in the question.

Question 6. [15 Marks]
Write a program to input a number and print whether the number is a special number or not.
(A number is said to be a special number, if the sum of the factorial of the digits of the number is same as the original number).
Example : 145 is a special number, because 1!+4!+5! = 1+24+120=145
(Where ! stands for factorial of the number and the factorial value of a number is the product of all integers from 1 to that number, example 5!= 1*2*3*4*5=120).

Answer:

import java.util.Scanner;
public class SpecialNumber {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.println("Enter a number:");
        int n = sc.nextInt();
        int temp = n;
        int sum = 0;
        
        while (temp > 0) {
            int d = temp % 10;
            int fact = 1;
            for (int i = 1; i <= d; i++) {
                fact *= i;
            }
            sum += fact;
            temp /= 10;
        }
        
        if (sum == n) {
            System.out.println(n + " is a special number.");
        }
        else {
            System.out.println(n + " is not a special number.");
        }
    }
}

Teacher's Note:
a) Ensure the factorial is calculated separately for each extracted digit.
b) Always store the original number in a temporary variable because the number is modified during digit extraction.

Question 7. [15 Marks]
Write a program to accept a word and convert it into lowercase if it is in uppercase, and display the new word by replacing only the vowels with the character following it.
Example :
Sample Input : computer
Sample Output : cpmpvtfr

Answer:

import java.util.Scanner;
public class VowelReplace {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.println("Enter a word:");
        String s = sc.next();
        s = s.toLowerCase();
        String res = "";
        
        for (int i = 0; i < s.length(); i++) {
            char ch = s.charAt(i);
            if (ch == 'a' || ch == 'e' || ch == 'i' || ch == 'o' || ch == 'u') {
                ch = (char)(ch + 1);
            }
            res += ch;
        }
        
        System.out.println("Sample Output : " + res);
    }
}

Teacher's Note:
a) Vowels ('a', 'e', 'i', 'o', 'u') are checked, and their ASCII values are incremented by 1 using typecasting.
b) The sample input 'computer' has vowels 'o' (becomes 'p') and 'u' (becomes 'v'), leading to output 'cpmpvtfr'.

Question 8. [15 Marks]
Design a class to overload a function compare() as follows :
(a) void compare(int, int) - to compare two integer values and print the greater of the two integers.
(b) void compare(char, char) - to compare the numeric value of two characters and print the character with higher numeric value.
(c) void compare(String, String) - to compare the length of the two strings and print the longer of the two.

Answer:

public class OverloadCompare {
    void compare(int a, int b) {
        if (a > b) {
            System.out.println(a + " is greater.");
        }
        else {
            System.out.println(b + " is greater.");
        }
    }
    
    void compare(char c1, char c2) {
        if (c1 > c2) {
            System.out.println(c1 + " has higher numeric value.");
        }
        else {
            System.out.println(c2 + " has higher numeric value.");
        }
    }
    
    void compare(String s1, String s2) {
        if (s1.length() > s2.length()) {
            System.out.println(s1 + " is longer.");
        }
        else {
            System.out.println(s2 + " is longer.");
        }
    }
}

Teacher's Note:
a) All methods share the same name compare() but have different parameter signatures (int/int, char/char, String/String).
b) Character comparison automatically compares their Unicode (ASCII) values in Java.

Question 9. [15 Marks]
Write a menu driven program to perform the following : (Use switch - case statement)
(a) To print the series 0, 3, 8, 15, 24 ..... n terms (value of 'n' is to be an input by the user.)
(b) To find the sum of the series given below :
S = 1/2 + 3/4 + 5/6 + 7/8 -------- 19/20.

Answer:

import java.util.Scanner;
public class SeriesMenu {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.println("Press 1 for Series 0, 3, 8, 15, 24...");
        System.out.println("Press 2 for Sum of Series S = 1/2 + 3/4 + ...");
        int ch = sc.nextInt();
        
        switch (ch) {
            case 1:
                System.out.println("Enter value of n:");
                int n = sc.nextInt();
                for (int i = 1; i <= n; i++) {
                    int term = (i * i) - 1;
                    System.out.print(term + " ");
                }
                break;
            
            case 2:
                double sum = 0.0;
                for (int i = 1; i <= 19; i += 2) {
                    sum += (double)i / (i + 1);
                }
                System.out.println("Sum of series = " + sum);
                break;
            
            default:
                System.out.println("Invalid choice!");
        }
    }
}

Teacher's Note:
a) For part (a), notice the pattern: \(1^2-1=0\), \(2^2-1=3\), \(3^2-1=8\), etc.
b) For part (b), typecast to double during division to prevent integer division truncation.