Question

Write a method is Even that uses the remainder operator (\%) to determine whether an integer is even. The method should take an integer argument and return true if the integer is even and \(f\) al se otherwise. Incorporate this method into an application that inputs a sequence of integers (one at a time) and determines whether each is even or odd.

Short answer

The isEven method returns true if an integer is even (remainder of division by 2 is zero), and false otherwise. The main application takes user input, calls isEven for each input, and reports if it's even or odd.

Step-by-step solution

Define the method isEven

Create a method named isEven that accepts an integer parameter. Inside the method, use the remainder operator (%) to determine if the integer is even by checking if the number divided by 2 has a remainder of zero. If the remainder is zero, return true, indicating the number is even; otherwise, return false.

Implement the method in an application

Develop an application (main method) that allows the user to input a sequence of integers. For each input, call the isEven method and pass the integer as an argument. Display the result to the user, informing them whether the number is even or odd.

Test the application

After implementing the application, perform tests by entering various integers to ensure that the method correctly identifies each number as even or odd. Verify that even numbers return true and odd numbers return false when passed to the isEven method.

Key concepts

Remainder Operator

In Java, the remainder operator, denoted as the percentage symbol (%), is a powerful tool used to obtain the remainder of a division between two numbers. For instance, in the expression \(5 \% 2\), the remainder operator will yield the result 1, because when 5 is divided by 2, a remainder of 1 is left after the division.

Understanding how this operator works is essential when you need to perform operations that depend on divisibility, such as checking if a number is even or odd. If a number is even, dividing it by 2 will result in a remainder of 0. Contrarily, dividing an odd number by 2 will always give a non-zero remainder. This characteristic is what we exploit in our method implementation to check for even or odd integers.

Practical Usage of Remainder Operator

One practical use of the remainder operator is to determine the evenness or oddness of integers, as we do in our example. This operator underpins the logic behind many algorithms and can be used in various programming scenarios, such as looping through a circular list, creating hash functions, or implementing digital clocks that wrap around after 60 seconds or minutes.

Method Implementation

Implementing a method in Java involves defining a set of instructions that can be reused throughout your program. The method performs a specific task and can optionally return a value. In our exercise, the method named \(\text{isEven}\) encapsulates the logic to determine whether a given integer is even.

To create a method, start with its access modifier, return type, method name, and parameters. In this example, our method has a return type of 'boolean' because it yields a true or false value. It takes one parameter: an integer which it will assess for evenness. The beauty of method implementation lies in the organization and encapsulation of code functionality, making it easy to read and maintain.

Reusable Code Blocks

Once implemented, methods can be called multiple times with different arguments, which means you can efficiently perform the same operation on various inputs without rewriting code. This concept is a fundamental principle of good programming practices, enhancing code readability and reducing potential errors.

Integer Number Check

An integer number check in Java is a way of determining certain properties of a number, such as whether it is positive, negative, or, as highlighted by our original exercise, whether it is even or odd. This involves evaluating the number against specific conditions and returning a boolean result based on that evaluation.

When incorporating an integer number check into your program, it's important to understand the types of numbers you will be dealing with and possible edge cases. For example, when checking if a number is even, it's also good to consider what should happen if the number is zero, which is technically an even number, or if it is negative.

Edge Case Considerations

Thinking about and correctly handling edge cases can prevent bugs and make sure your application behaves predictably in all circumstances. Always remember to test your application with a range of inputs, including typical use cases as well as edge cases, to ensure comprehensive coverage and correct functionality.