What is Unary Operators in Java? 

What is Unary Operators in Java? 

Unary operators in Java are operators that operate on a single operand to perform various operations, such as incrementing/decrementing a value, negating a boolean value, or inverting the sign of a number. Java provides several unary operators:

1. Unary Plus (+)
2. Unary Minus (–)
3. Increment (++)
4. Decrement (—)
5. Logical NOT (!)

1. Unary Plus (+) #

The unary plus operator is used to indicate a positive value. Though it doesn’t change the value, it’s sometimes used for code readability.

Example:

public class UnaryOperatorExample {

    public static void main(String[] args) {

        int a = +5; // Positive value

        System.out.println("a = " + a); 

    }

}

Output: 
a = 5

2. Unary Minus (–) #

The unary minus operator negates the value of the operand, effectively changing its sign.

Example:

public class UnaryOperatorExample {

    public static void main(String[] args) {

        int a = 5;

        int b = -a; // Negates the value of a

        System.out.println("b = " + b); 

    }

}

Output: 
b = -5

3. Increment (++) #

The increment operator increases the value of the operand by 1. It has two forms:

• Prefix Increment (++a): Increments the value before using it in an expression.
• Postfix Increment (a++): Uses the current value in an expression, then increments it.

Example:

public class UnaryOperatorExample {

    public static void main(String[] args) {

        int a = 5;

        // Prefix: a is incremented to 6, then b is assigned 6
        int b = ++a; 

        System.out.println("a = " + a + ", b = " + b); 

        int c = 5;

        // Postfix: d is assigned 5, then c is incremented to 6
        int d = c++; 

        System.out.println("c = " + c + ", d = " + d); 

    }

}

Output: 
a = 6, b = 6

4. Decrement (—) #

The decrement operator decreases the value of the operand by 1. It also has two forms:

• Prefix Decrement (–a): Decrements the value before using it in an expression.
• Postfix Decrement (a–): Uses the current value in an expression, then decrements it.

Example:

public class UnaryOperatorExample {

    public static void main(String[] args) {

        int a = 5;

        // Prefix: a is decremented to 4, then b is assigned 4
        int b = --a; 

        System.out.println("a = " + a + ", b = " + b); 

        int c = 5;
 
        // Postfix: d is assigned 5, then c is decremented to 4
        int d = c--; 

        System.out.println("c = " + c + ", d = " + d); 

    }

}

Output: 
a = 4, b = 4
c = 4, d = 5

5. Logical NOT (!) #

The logical NOT operator inverts the boolean value of the operand. If the operand is true, it becomes false, and vice versa.

Example:

public class UnaryOperatorExample {

    public static void main(String[] args) {

        boolean isTrue = true;

        // Inverts the value of isTrue
        boolean isFalse = !isTrue; 

        System.out.println("isTrue = " + isTrue); 

        System.out.println("isFalse = " + isFalse);

    }

}

Output: 
isTrue = true
isFalse = false

Summary #

Unary operators in Java are powerful tools for performing basic operations on single operands, such as changing signs, incrementing/decrementing values, or inverting booleans. They are essential for writing concise and efficient code in various programming scenarios.