Java Logical OR Operator

1. Java Logical OR Operator

In this lesson of our Java course, we will take a look at the Java logical OR operator. In the realm of programming, logical operators serve as the backbone of decision-making and condition evaluation. Among these operators, the logical OR operator stands out for its ability to facilitate intricate decision logic and control the flow of code. In this comprehensive article, we will delve into the Java logical OR operator (||), unraveling its functionality, use cases, and providing a plethora of illustrative examples.

2. Unveiling the Java Logical OR Operator

The logical OR operator (||) in Java is a fundamental tool that allows programmers to combine multiple conditions and make decisions based on whether at least one condition is true. It returns true if either or both of the conditions being evaluated are true, and only returns false if both conditions are false. Much like its logical AND counterpart, the logical OR operator is a binary operator, operating on two operands.

Syntax

The syntax of the logical OR operator is as follows:

boolean result = expression1 || expression2;

Here, expression1 and expression2 are boolean expressions being combined.

3. Examples Demonstrating the Java Logical OR Operator

Let’s delve into various scenarios where the logical OR operator can be harnessed to make informed decisions and shape the flow of code.

3.1. Example 1: Enabling Discount for VIP Customers

public class DiscountExample {
    public static void main(String[] args) {
        boolean isVipCustomer = true;
        boolean hasCouponCode = false;

        if (isVipCustomer || hasCouponCode) {
            System.out.println("Congratulations! You qualify for a discount.");
        } else {
            System.out.println("Sorry, no discount available for you.");
        }
    }
}

In this example, the logical OR operator is employed to find out whether a customer, either VIP or possessing a valid coupon code, is eligible for a discount.

3.2. Example 2: Accepting User Input

public class UserInputExample {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        
        System.out.print("Enter your age: ");
        int age = scanner.nextInt();
        
        System.out.print("Do you have a valid ID? (true/false): ");
        boolean hasValidID = scanner.nextBoolean();
        
        if (age >= 18 || hasValidID) {
            System.out.println("Access granted.");
        } else {
            System.out.println("Access denied.");
        }
        
        scanner.close();
    }
}

Here, the logical OR operator is used to decide whether a user should be granted access based on either being of legal age or possessing a valid ID.

3.3. Example 3: Checking Prime Numbers

public class PrimeNumberExample {
    public static void main(String[] args) {
        int number = 17;
        boolean isDivisible = false;

        for (int i = 2; i <= number / 2; ++i) {
            if (number % i == 0) {
                isDivisible = true;
                break;
            }
        }

        if (!isDivisible || number <= 1) {
            System.out.println(number + " is a prime number.");
        } else {
            System.out.println(number + " is not a prime number.");
        }
    }
}

In this example, the logical OR operator is leveraged to identify whether a number is prime, based on the absence of any divisors other than 1 and itself.

4. Short-Circuit Evaluation: A Hidden Gem

Similar to the logical AND operator, the logical OR operator also employs short-circuit evaluation. If the first operand of the || operator evaluates to true, the second operand is not evaluated because the entire expression is already guaranteed to be true.

public class ShortCircuitEvaluationExample {
    public static void main(String[] args) {
        int x = 10;
        int y = 0;

        if (x != 0 || y / x > 2) {
            System.out.println("Condition is true.");
        } else {
            System.out.println("Condition is false.");
        }
    }
}

Here, even though y / x would lead to a division by zero error, the code doesn’t crash because the second operand is not evaluated because of short-circuiting.

Conclusion

The Java logical OR operator (||) is a cornerstone of programming logic, empowering developers to craft intricate decision-making scenarios and control program execution. By skillfully combining boolean expressions, programmers can create responsive and dynamic applications that adapt to varying conditions. Through a series of diverse examples, we’ve explored how the logical OR operator can be wielded to enable discounts, grant access, and determine prime numbers.

We’ve also unraveled the concept of short-circuit evaluation, a feature that optimizes code execution and enhances efficiency. Armed with this knowledge, we’re poised to elevate our Java programming skills and craft more sophisticated, responsive, and robust applications.As always, the source code for this course is available on our GitHub Repository.