Core Java: Increment/Decrement

Java supports these unary arithmetic operators: increment (++) and decrement (--) for all numeric primitive types (byte, short, char, int, long, float and double, except boolean).

 

Operator	Description	Example
++	Increment the value of the variable by 1. x++ or ++x is the same as x += 1 or x = x + 1	int x = 5; x++; // x is 6 ++x; // x is 7
--	Decrement the value of the variable by 1. x-- or --x is the same as x -= 1 or x = x – 1	int y = 6; y--; // y is 5 --y; // y is 4
Operatr	Description	Example
++var	Pre-Increment Increment var, then use the new value of var	y = ++x; same as x=x+1; y=x;
var++	Post-Increment Use the old value of var, then increment var	y = x++; same as oldX=x; x=x+1; y=oldX;
--var	Pre-Decrement	y = --x; same as x=x-1; y=x;
var--	Post-Decrement	y = x--; same as oldX=x; x=x-1; y=oldX;

 

For examples,

 

x = 5;

System.out.println(x++);  // Print x (5), then increment x (=6). Output is 5. (x++ returns the oldX.)

 

x = 5;

System.out.println(++x);  // Increment x (=6), then print x (6). Output is 6. (++x returns x+1.)

 

Prefix operator (e.g, ++i) could be more efficient than postfix operator (e.g., i++)?!