Chapter 12 Exercises

Exercise 1. Division by zero. Write a Program that asks the user for two numbers and tries to divide the first by the second. Handle the ArithmeticException in case of division by zero.

Solution

import java.util.Scanner;
public class Main {
    public static void main(String[] args) {

        Scanner scanner = new Scanner(System.in);
        
        System.out.println("Enter the first number:");
        int num1 = scanner.nextInt();
        
        System.out.println("Enter the second number:");
        int num2 = scanner.nextInt();
        
        try {

            int result = num1 / num2;
            System.out.println("The result is: " + result);

        } catch (ArithmeticException e) {

            System.out.println("Error: Cannot divide by zero.");

        }
        
        scanner.close();

    }
}

Exercise 2. Handling NumberFormatException: Write a Program that asks the user for an integer number and tries to convert it. Handle the NumberFormatException in case the format is not valid. Once the exercise is completed, try entering a decimal number to see what happens.

Solution:

import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        
        System.out.println("Enter an integer number:");
        String input = scanner.nextLine();
        
        try {

            int number = Integer.parseInt(input);
            System.out.println("The entered number is: " + number);

        } catch (NumberFormatException e) {

            System.out.println("Error: Invalid number format.");

        }
        
        scanner.close();

    }
}

Exercise 3. Out of range index in an array. Write a Program that creates an array of 5 elements and tries to access a position out of range. Handle the ArrayIndexOutOfBoundsException.

Solution:

public class Main {
    public static void main(String[] args) {

        int[] array = {1, 2, 3, 4, 5};
        
        try {

            int value = array[10];
            System.out.println("The value is: " + value);

        } catch (ArrayIndexOutOfBoundsException e) {

            System.out.println("Error: Index out of range.");

        }
    }
}

Exercise 4. Invalid arithmetic operation. Write a Program that asks the user for two numbers and subtracts them. Handle the ArithmeticException if the operation is not valid for any reason (e.g., subtraction of extremely large values).

Solution:

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        
        System.out.println("Enter the first number:");
        long num1 = scanner.nextLong();
        
        System.out.println("Enter the second number:");
        long num2 = scanner.nextLong();
        
        try {

            long result = Math.subtractExact(num1, num2);
            System.out.println("The result is: " + result);

        } catch (ArithmeticException e) {

            System.out.println("Error: Invalid arithmetic operation.");

        }
        
        scanner.close();

    }
}

Exercise 5. String concatenation. Write a Program that tries to concatenate a very large number of strings, causing an OutOfMemoryError. Handle the exception.

Solution:

public class Main {
    public static void main(String[] args) {
        
        try {

            String str = "";
            for (int i = 0; i < Integer.MAX_VALUE; i++) {
                str += "a";

            }

        } catch (OutOfMemoryError e) {

            System.out.println("Error: Insufficient memory for the operation.");

        }
    }
}