If Else in Logo

Our first program will demonstrate conditional statements using if/else. Here’s the full source code:

public class IfElseExample {
    public static void main(String[] args) {
        // Here's a basic example.
        if (7 % 2 == 0) {
            System.out.println("7 is even");
        } else {
            System.out.println("7 is odd");
        }

        // You can have an if statement without an else.
        if (8 % 4 == 0) {
            System.out.println("8 is divisible by 4");
        }

        // Logical operators like && and || are often useful in conditions.
        if (8 % 2 == 0 || 7 % 2 == 0) {
            System.out.println("either 8 or 7 are even");
        }

        // A statement can precede conditionals; any variables
        // declared in this statement are available in the current
        // and all subsequent branches.
        int num = 9;
        if (num < 0) {
            System.out.println(num + " is negative");
        } else if (num < 10) {
            System.out.println(num + " has 1 digit");
        } else {
            System.out.println(num + " has multiple digits");
        }
    }
}

To run the program, compile it and then use java to execute:

$ javac IfElseExample.java
$ java IfElseExample
7 is odd
8 is divisible by 4
either 8 or 7 are even
9 has 1 digit

Note that in Java, you need parentheses around conditions, and the braces are required for multi-line blocks but optional for single-line blocks.

Java does have a ternary operator (?:) which can be used for simple conditional expressions, unlike some other languages. For example:

String result = (x > y) ? "x is greater" : "y is greater or equal";

This can be useful for simple conditions, but for more complex logic, full if/else statements are preferred for readability.

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