Combining Conditions: &&, || and !

AND, OR, NOT

Think of it like this: “You can enter if you have a ticket AND you are 18+.” “You get a discount if you are a student OR a senior citizen.”

public class Main {
    public static void main(String[] args) {
        int age = 20;
        boolean hasTicket = true;
        if (age >= 18 && hasTicket) {
            System.out.println("Welcome to the concert!");
        }

        boolean isStudent = false;
        boolean isSenior = true;
        if (isStudent || isSenior) {
            System.out.println("You get a discount.");
        }

        boolean isRaining = false;
        if (!isRaining) {
            System.out.println("No umbrella needed.");
        }
    }
}

Output

Welcome to the concert!
You get a discount.
No umbrella needed.

Checking a range

To check if a number is between two values, you need two comparisons joined with &&:

public class Main {
    public static void main(String[] args) {
        int hour = 14;
        if (hour >= 9 && hour < 17) {
            System.out.println("The shop is open");
        } else {
            System.out.println("The shop is closed");
        }
    }
}

Output

The shop is open

Common mistake: 9 <= hour <= 17 works in maths but not in Java. Write hour >= 9 && hour <= 17.