Check-Even Number Function()

Step 1: Understand the problem

The first step in this task is understanding what we want to achieve. Our task is to write a function in Java that checks whether a number is even or not. An even number is an integer which is 'evenly divisible' by two. This means there is no remainder if you divide by 2. If there is a remainder, then the number is odd.

Step 2: Build the basic Java function structure

We will start by creating a new function in Java. This usually involves defining the public or private scope, the return type, the function name, and any inputs in parentheses. In our case, the function will be public, will return a boolean (true or false) and we will name it isEven. It will have one input: the integer, num, which we want to check if it's even or not.

public boolean isEven(int num) {

}

Step 3: Implement the Check

Now that we have the basic structure of our function, we'll add the logic needed to determine if the number is even or not. This involves using the modulo operator '%' which returns the remainder of a division. If a number mod 2 is equal to 0, that means it's evenly divisible by 2 and therefore it's even.

public boolean isEven(int num) {
   return num % 2 == 0;
}

Step 4: Testing the function

Once we've written our function, it's important to test it to make sure it behaves as expected. We can do this by calling the function with some test numbers. For example, we'll test our function isEven with arguments 4, 15 and 0

public static void main(String[] args) {
    System.out.println(isEven(4));  // true
    System.out.println(isEven(15)); // false
    System.out.println(isEven(0));  // true
}

Conclusion

The function we have written successfully checks whether a number is even or not. It does this by utilizing the modulo operator in Java, which returns the remainder of a division. If the remainder of the division of the number by 2 equals to zero, then the number is even. Here is the full implementation of our function:

public class Main {
    public static void main(String[] args) {
        System.out.println(isEven(4));  // true
        System.out.println(isEven(15)); // false
        System.out.println(isEven(0));  // true
    }

    public static boolean isEven(int num) {
        return num % 2 == 0;
    }
}

This code provides a concise and efficient way to determine if a number is even in Java.