ICSE Computer Application - Class X - MCQ - CALCUTTA PUBLIC SCHOOL - Quiz

Let's break down the two string method operations in Java for the string "MISSISSIPPI":

1. "MISSISSIPPI".indexOf('S')

The indexOf('S') method returns the index of the first occurrence of the character 'S' in the string "MISSISSIPPI".

• The string "MISSISSIPPI" has the following indices:

  
  M  I  S  S  I  S  S  I  P  P  I
  0  1  2  3  4  5  6  7  8  9 10
  
  

• The first occurrence of 'S' is at index 2.

So, "MISSISSIPPI".indexOf('S') returns 2.

2. "MISSISSIPPI".lastIndexOf('I')

The lastIndexOf('I') method returns the index of the last occurrence of the character 'I' in the string "MISSISSIPPI".

• From the same index mapping, the last occurrence of 'I' is at index 10.

So, "MISSISSIPPI".lastIndexOf('I') returns 10.

Addition Operation

Now, adding these two results together:

indexOf('S') + lastIndexOf('I')
= 2 + 10
= 12

So, the correct answer is:

12

Let's analyze the given Java program to determine its output.

Code:

int a = 2;
switch (a) {
    case 1: 
        System.out.print("Tiger");
    case 2: 
        System.out.print("Deer");
    default: 
        System.out.print("Lion");
}
        

Explanation:

1. Initialization:

   int a = 2;
   The variable a is initialized with the value 2.

2. Switch Statement:

   switch (a) {
   The switch statement checks the value of a:

   • Case 1:

     Since a is 2, it does not match case 1, so the code inside case 1 is not executed.

   • Case 2:

     The value of a matches case 2, so the statement inside case 2 is executed:
     System.out.print("Deer");
     This prints Deer.

   • Default Case:

     Since there is no break statement, the execution falls through to the default case:
     System.out.print("Lion");
     This prints Lion.

3. Output:

   The output of the program is:
   DeerLion

Conclusion:

The correct answer is: c) DeerLion

Let's determine the final values stored in the variables x and y based on the given code:

Code:

double a = 6.35;
double b = 14.74;

double x = Math.abs(Math.ceil(a));
double y = Math.rint(Math.max(a, b));
        

Explanation:

1. Calculating the Value of x:

   Math.ceil(a):
   The Math.ceil(x) method returns the smallest integer greater than or equal to x.
   For a = 6.35, Math.ceil(6.35) returns 7.0.

   Math.abs(Math.ceil(a)):
   The Math.abs(x) method returns the absolute value of x.
   Since Math.ceil(a) is 7.0, and 7.0 is already positive, Math.abs(7.0) remains 7.0.

   So, the value of x is 7.0.

2. Calculating the Value of y:

   Math.max(a, b):
   The Math.max(x, y) method returns the greater of the two values.
   For a = 6.35 and b = 14.74, Math.max(6.35, 14.74) returns 14.74.

   Math.rint(Math.max(a, b)):
   The Math.rint(x) method returns the double value that is closest to x. If two double values are equally close, the even one is returned.
   For Math.max(a, b) which is 14.74, Math.rint(14.74) returns 15.0 because 15.0 is the nearest integer to 14.74.

   So, the value of y is 15.0.

Conclusion:

The final values stored in variables x and y are:

• x: 7.0
• y: 15.0

Automatic conversion of primitive data into an object of a wrapper class is called autoboxing.

Explanation:

• Autoboxing is a feature in Java that allows automatic conversion between primitive types (such as int, float, double, etc.) and their corresponding wrapper classes (such as Integer, Float, Double, etc.).
• For example, Java automatically converts an int to an Integer when it is assigned to an Integer object or used in a context where an Integer is expected.

Correct Answer:

a) autoboxing

The parseLong() function is a member of the Long wrapper class.

Explanation:

• parseLong() is a static method provided by the Long wrapper class in Java.
• It is used to convert a String into a long value.

Correct Answer:

a) Long wrapper class

To stop the execution of a construct, such as a loop or a switch statement, the correct statement is:

b) break

Explanation:

• break: This statement is used to exit from a loop (like for, while, or do-while) or a switch statement. When break is encountered, the execution of the loop or switch construct is immediately terminated.

• System.exit(0): This terminates the entire Java Virtual Machine (JVM), not just a single construct.

• stop: This is not a valid Java statement for stopping execution.

• end: This is not a valid Java statement for stopping execution.

Correct Answer:

b) break

Let's analyze the corrected Java code to determine its type:

Corrected Code:

class Out {

    int a = 5; // Adding a variable to compare with x

    int cal() {
        int x = 10;
        if (x > a) {
            return --x; // Decrements x by 1 and returns 9
        } else {
            return ++x; // Increments x by 1 and returns 11
        }
    }

    public static void main(String[] args) {
        Out ob = new Out(); // Create an instance of the class
        int x = ob.cal(); // Call the method cal() and store the result in x
        System.out.println(x); // Print the value of x
    }
}
        

Explanation:

The method cal() performs an operation based on the class-level variable a and modifies the value of x. It returns 9 in this case, because x is greater than a.
- The method is considered an impure method because it depends on and operates based on mutable state.

Answer:

The program demonstrates an example of an Impure Method.

• Class and Main Method:

  • The class MCQ contains the main method, which is the entry point for the program.
  • Inside the main method, an instance of MCQ is created, and the test method is called with the argument 12.

• Method test:

  • The test method takes an integer n as a parameter.
  • It iterates through numbers from 1 to n (inclusive) using a for loop.
  • Inside the loop, it checks if n is divisible by x using the condition if (n % x == 0).
  • If the condition is true, it prints the value of x followed by a space.

• Output Calculation:

  • The test method is called with n = 12.
  • The loop iterates from 1 to 12 and checks for divisibility.
  • The numbers that divide 12 without leaving a remainder (i.e., the factors of 12) are 1, 2, 3, 4, 6, and 12.

nested loop

Certainly! Here is an example of a nested loop in Java:

public class NestedLoopExample {
    public static void main(String[] args) {
        // Outer loop
        for (int i = 1; i <= 3; i++) {
            System.out.println("Outer loop iteration: " + i);

            // Inner loop
            for (int j = 1; j <= 2; j++) {
                System.out.println("  Inner loop iteration: " + j);
            }
        }
    }
}

Output:

Outer loop iteration: 1
  Inner loop iteration: 1
  Inner loop iteration: 2
Outer loop iteration: 2
  Inner loop iteration: 1
  Inner loop iteration: 2
Outer loop iteration: 3
  Inner loop iteration: 1
  Inner loop iteration: 2

In this example, the outer loop runs 3 times, and for each iteration of the outer loop, the inner loop runs 2 times. This demonstrates how nested loops work in Java.

The break statement is used to exit the current loop.

Here is an example in Java to demonstrate its usage:

public class BreakStatementExample {
    public static void main(String[] args) {
        // Loop from 1 to 5
        for (int i = 1; i <= 5; i++) {
            if (i == 3) {
                break; // Exit the loop when i is 3
            }
            System.out.println("Iteration: " + i);
        }
        System.out.println("Loop exited.");
    }
}

Output:

Iteration: 1
Iteration: 2
Loop exited.

In this example, the break statement exits the loop when i equals 3, so the loop stops executing and the program continues with the next statement after the loop.