Assignment Operators in Java

What are Assignment Operators in Java?

Assignment Operators in Java are used to assign values to variables. Beyond the simple assignment operator =, Java provides a variety of compound assignment operators that combine an operation with assignment, making code shorter and easier to read.

Simple Assignment Operator (=)

The most basic assignment operator is =. It assigns the value on its right to the variable on its left.

Example of Simple Assignment

int x = 10;  // assigns the value 10 to variable x
System.out.println(x);  // Output: 10

Compound Assignment Operators

Compound assignment operators combine a mathematical or bitwise operation with assignment. For example, += adds a value to a variable and assigns the result back to that variable.

This reduces repetition and enhances code clarity.

Common Compound Assignment Operators

• += (Add and assign)
• -= (Subtract and assign)
• *= (Multiply and assign)
• /= (Divide and assign)
• %= (Modulus and assign)
• &= (Bitwise AND and assign)
• |= (Bitwise OR and assign)
• ^= (Bitwise XOR and assign)
• <<= (Left shift and assign)
• >>= (Right shift and assign)
• >>>= (Unsigned right shift and assign)

Examples of Compound Assignment Operators

int a = 10;

a += 5;   // equivalent to a = a + 5
System.out.println(a);  // Output: 15

a -= 3;   // equivalent to a = a - 3
System.out.println(a);  // Output: 12

a *= 2;   // equivalent to a = a * 2
System.out.println(a);  // Output: 24

a /= 4;   // equivalent to a = a / 4
System.out.println(a);  // Output: 6

a %= 4;   // equivalent to a = a % 4
System.out.println(a);  // Output: 2

Bitwise Compound Assignment Operators

You can also combine bitwise operations with assignment using operators like &=, |=, and ^=. These are especially useful when working with flags or binary data.

Example of Bitwise Assignment

int flags = 0b1010;  // binary: 1010

flags &= 0b1100;     // bitwise AND and assign (1010 & 1100 = 1000)
System.out.println(Integer.toBinaryString(flags));  // Output: 1000

flags |= 0b0011;     // bitwise OR and assign (1000 | 0011 = 1011)
System.out.println(Integer.toBinaryString(flags));  // Output: 1011

flags ^= 0b0101;     // bitwise XOR and assign (1011 ^ 0101 = 1110)
System.out.println(Integer.toBinaryString(flags));  // Output: 1110

Why Use Assignment Operators?

Compound assignment operators help keep your code concise and readable. They reduce redundancy by eliminating the need to repeat the variable name on both sides of the assignment, which also minimizes the chance of mistakes.

Summary

Assignment Operators in Java are fundamental tools for managing variables and performing operations efficiently.

Whether you’re simply assigning values or combining arithmetic and bitwise operations with assignment, mastering these operators will improve your coding fluency and style.