Assignment: Java Basics
Multiple Choice Questions (MCQs)
Q.1. Which of the following is not a valid Java data type?
(a) int
(b) float
(c) string
(d) boolean
Ans. (c)
Q.2. What is the correct syntax to declare a variable in Java?
(a) int x;
(b) variable x;
(c) x = int;
(d) declare int x;
Ans. (a)
Q.3. Which of the following is a valid Java identifier?
(a) 2variable
(b) my_variable
(c) #variable
(d) variable&name
Ans. (b)
Q.4. What is the output of the following code snippet?
int x = 5;
int y = 2;
System.out.println(x / y);
(a) 2
(b) 2.5
(c) 3
(d) 2.0
Ans. (c)
Q.5. Which operator is used for concatenating strings in Java?
(a) +
(b) *
(c) /
(d) -
Ans. (a)
High Order Thinking Questions (HOTS)
Q.1. Write a Java code snippet to swap the values of two variables without using a temporary variable.
int a = 5;
int b = 10;
a = a + b;
b = a - b;
a = a - b;
Q.2. Explain the difference between the prefix and postfix increment operators in Java with an example.
The prefix increment operator (++x) increments the value of x and then returns the new value, while the postfix increment operator (x++) returns the current value of x and then increments it.
Q.3. Write a Java code snippet to calculate the factorial of a given number using a recursive function.
public class Factorial {
public static int calculateFactorial(int n) {
if (n == 0)
return 1;
else
return n * calculateFactorial(n - 1);
}
public static void main(String[] args) {
int number = 5;
int factorial = calculateFactorial(number);
System.out.println("Factorial of " + number + " is: " + factorial);
}
}
Q.4. Explain the concept of type conversion in Java and provide an example.
Type conversion in Java is the process of converting one data type to another.
For example:
int x = 5;
double y = x; // Implicit type conversion (widening conversion)
Q.5. Write a Java code snippet to determine whether a given year is a leap year or not.
public class LeapYear {
public static void main(String[] args) {
int year = 2023;
boolean isLeapYear = false;
if (year % 4 == 0) {
if (year % 100 == 0) {
if (year % 400 == 0)
isLeapYear = true;
} else {
isLeapYear = true;
}
}
if (isLeapYear)
System.out.println(year + " is a leap year.");
else
System.out.println(year + " is not a leap year.");
}
}
Fill in the Blanks
Q.1. The process of combining two or more strings in Java is known as ____________.
Ans. concatenation
Q.2. A variable that is declared inside a method is called a ____________ variable.
Ans. local
Q.3. The data type used to represent a single character in Java is ____________.
Ans. char
Q.4. Java supports ____________ type conversion between compatible data types.
Ans. implicit
Q.5. The ____________ operator in Java is used to assign a value to a variable.
Ans. = (equal sign)
True or False
1. Java is a platform-independent programming language. (True/False)
Ans. True
2. The '==' operator in Java compares the values of two variables. (True/False)
Ans. True
3. A switch statement can be used to replace multiple if-else statements in Java. (True/False)
Ans. True
4. In Java, the '&&' operator returns true if both operands are true. (True/False)
Ans. True
5. Java supports automatic type conversion from double to int. (True/False)
Ans. False
Hands-On Questions
Q.1. Write a Java code snippet to calculate the area of a circle with a given radius. (Use the value of π as 3.14)
import java.util.Scanner;
public class CircleArea {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.print("Enter the radius of the circle: ");
double radius = scanner.nextDouble();
double area = 3.14 * radius * radius;
System.out.println("The area of the circle is: " + area);
}
}
Q.2. Write a Java code snippet to print the Fibonacci series up to the nth term.
import java.util.Scanner;
public class FibonacciSeries {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
System.out.print("Enter the value of n: ");
int n = scanner.nextInt();
int firstTerm = 0, secondTerm = 1;
System.out.print("Fibonacci Series up to " + n + " terms: ");
for (int i = 1; i <= n; i++) {
System.out.print(firstTerm + " ");
int nextTerm = firstTerm + secondTerm;
firstTerm = secondTerm;
secondTerm = nextTerm;
}
}
}
Q.3. Write a Java program to find the largest element in an array.
public class LargestElement {
public static void main(String[] args) {
int[] numbers = {10, 5, 20, 8, 15};
int largest = numbers[0];
for (int i = 1; i < numbers.length; i++) {
if (numbers[i] > largest) {
largest = numbers[i];
}
}
System.out.println("The largest element is: " + largest);
}
}
Q.4. Write a Java code snippet to reverse a string without using any built-in functions or methods.
public class ReverseString {
public static void main(String[] args) {
String originalString = "Hello, World!";
char[] chars = originalString.toCharArray();
int length = chars.length;
char[] reversedChars = new char[length];
for (int i = 0; i < length; i++) {
reversedChars[i] = chars[length - 1 - i];
}
String reversedString = new String(reversedChars);
System.out.println("Reversed string: " + reversedString);
}
}
Q.5. Write a Java code snippet to check whether a given string is a palindrome or not.
public class Palindrome {
public static void main(String[] args) {
String originalString = "level";
int length = originalString.length();
boolean isPalindrome = true;
for (int i = 0; i < length / 2; i++) {
if (originalString.charAt(i) != originalString.charAt(length - 1 - i)) {
isPalindrome = false;
break;
}
}
if (isPalindrome)
System.out.println(originalString + " is a palindrome.");
else
System.out.println(originalString + " is not a palindrome.");
}
}
