Unary Operators in Java

Unary operators in Java are operators that work with only one operand. They are used to perform operations such as increasing or decreasing a value, changing the sign of a number, and reversing boolean values.

Unary operators are simple but very useful in Java programming, especially when working with loops, counters, calculations, and conditional statements.

What are Unary Operators in Java?

A unary operator is an operator that requires only a single operand to perform an operation.

Unlike binary operators that require two operands, unary operators work on only one value.

Syntax of Unary Operators in Java

The basic syntax of unary operators is:

operator operand;

Example of Unary Operator in Java

public class Main {
    public static void main(String[] args) {
        int number = 10; number++;
        System.out.println(number);
    }
}

In the above example, the increment operator (++) increases the value of the variable by 1.

Types of Unary Operators in Java

Java provides different types of unary operators to perform various operations on a single operand.

Java Unary Operators Table

Unary Plus Operator (+) in Java

The unary plus operator (+) is used to indicate that a value is positive. It does not change the value of the operand.

int  number = 10;
int result = +number; 
System.out.println(result);

Unary Minus Operator (-) in Java

The unary minus operator (-) changes the sign of a value. Positive values become negative and negative values become positive.

int number =  10;
int result = -number; 
System.out.println(result);

Increment Operator (++) in Java

The increment operator (++) increases the value of a variable by 1.

It can be used in two ways:

Prefix Increment Operator

In prefix increment, the value is increased first and then used in the expression.

int number = 5;
int  result = ++number;
System.out.println(result);

Postfix Increment Operator

In postfix increment, the current value is used first and then increased by 1.

int number = 5;
int result = number++;
System.out.println(result);
System.out.println(number);

Decrement Operator (--) in Java

The decrement operator (--) decreases the value of a variable by 1.

Similar to increment, decrement also has two forms:

Prefix Decrement Example

int number = 10;
int result = --number;
System.out.println(result);

Postfix Decrement Example

int  number = 10;
int result = number--;
System.out.println(result);
System.out.println(number);

Logical NOT Operator (!) in Java

The logical NOT operator (!) is used with boolean values. It reverses the result of a condition.

If the value is true, NOT changes it to false, and if the value is false, it changes it to true.

boolean status =  true;
System.out.println(!status);

Bitwise Complement Operator (~) in Java

The bitwise complement operator (~) is a unary operator that reverses all bits of an integer value.

It converts every 0 bit into 1 and every 1 bit into 0.

int number = 5;
System.out.println(~number);

Difference Between Prefix and Postfix Operators

Unary Operators Example with Multiple Operations

int number = 10;
System.out.println(++number);
System.out.println(--number);

Advantages of Unary Operators in Java

Common Mistakes While Using Unary Operators

Summary

Unary operators in Java operate on a single operand. They are used for changing values, increasing or decreasing numbers, and performing logical operations.

Java provides several unary operators such as unary plus (+), unary minus (-), increment (++), decrement (--), logical NOT (!), and bitwise complement (~).

Understanding unary operators is important for writing efficient Java programs, especially when working with loops, conditions, and calculations.