Increment and Decrement Operators

Short Answer:
Increment (++) increases a value by 1 and Decrement (--) decreases a value by 1.

Detailed Explanation:
Java provides two types of increment and decrement operators:

• Pre-Increment / Pre-Decrement
• Post-Increment / Post-Decrement

The difference depends on when the value is updated.

1. Pre-Increment (++a)

Short: Value increases first, then used.

int a = 5;
int b = ++a;   // a becomes 6, then assigned to b

Result: a = 6, b = 6

2. Post-Increment (a++)

Short: Value used first, then increased.

int a = 5;
int b = a++;   // b = 5, then a becomes 6

Result: a = 6, b = 5

3. Pre-Decrement (--a)

int a = 5;
int b = --a;   // a becomes 4, then assigned

4. Post-Decrement (a--)

int a = 5;
int b = a--;   // b = 5, then a becomes 4

Key Difference Table

Important Interview Points

• Works only with variables (not constants).
• Commonly used in loops.
• Be careful while using inside expressions.
• Pre and Post behave differently in complex statements.

Tricky Interview Example

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

Step-by-step: a++ → 5 (a becomes 6) ++a → 7 Result = 5 + 7 = 12