How to check the parity of a number in Java?

Checking the Parity of a Number in Java

Parity refers to the property of a number being either odd or even. In other words, parity is a way to determine whether a number is divisible by 2 without a remainder. Checking the parity of a number is a common task in programming, and Java provides several ways to accomplish this.

Using the Modulo Operator

The most straightforward way to check the parity of a number in Java is to use the modulo operator (%). The modulo operator returns the remainder of a division operation. If the remainder is 0, the number is even; otherwise, the number is odd.

Here's an example:

int number = 17;

if (number % 2 == 0) {
    System.out.println(number + " is even.");
} else {
    System.out.println(number + " is odd.");
}

In this example, the number 17 is checked for parity. The modulo operation number % 2 returns 1, which means 17 is an odd number.

Using the Bitwise AND Operator

Another way to check the parity of a number in Java is to use the bitwise AND operator (&). The bitwise AND operation compares the corresponding bits of two numbers and returns a 1 if both bits are 1, and 0 otherwise.

Here's an example:

int number = 24;

if ((number & 1) == 0) {
    System.out.println(number + " is even.");
} else {
    System.out.println(number + " is odd.");
}

In this example, the number 24 is checked for parity. The bitwise AND operation number & 1 returns 0, which means 24 is an even number.

The reason this works is that the last bit of an even number is always 0, and the last bit of an odd number is always 1. By performing the bitwise AND with 1, we can effectively check the last bit of the number to determine its parity.

Visualizing the Concept with a Mermaid Diagram

Here's a Mermaid diagram that illustrates the concept of checking the parity of a number using the modulo operator and the bitwise AND operator:

graph LR A[Number] --> B{Is the number even?} B -- Yes --> C[Number is even] B -- No --> D[Number is odd] C --> E[Use modulo operator (number % 2 == 0)] D --> F[Use bitwise AND operator (number & 1 == 0)]

The diagram shows that we can check the parity of a number by using either the modulo operator or the bitwise AND operator. If the result of the operation is 0, the number is even; otherwise, the number is odd.

Real-World Example: Checking Parity in a Dice Roll

Let's consider a real-world example to make the concept of parity more relatable. Imagine you're playing a board game that involves rolling a dice. You want to determine whether the dice roll resulted in an even or odd number.

In this case, you can use the parity of the dice roll to determine certain game mechanics. For example, if the game rules state that you can only move your game piece an even number of spaces on an even dice roll, you can use the parity of the dice roll to determine your next move.

By understanding how to check the parity of a number in Java, you can apply this knowledge to various real-world scenarios, making your programming skills more practical and applicable.