Arithmetic Assignment Operators

Statements like the following

a = a + 4;

can be rewritten as

a += 4;

Both statements perform the same action: they increase the value of a by 4.

Here is another example,

a = a % 2;

which can be expressed as

a %= 2;

In this case, the %= obtains the remainder of a/2 and puts that result back into a.

Any statement of the form

var = var op expression;

can be rewritten as

var op= expression;

Here is a sample program that shows several op= operator assignments:

 
public class Main {

  public static void main(String args[]) {
    int a = 1;
    int b = 2;
    int c = 3;

    a += 1;
    b *= 2;
    c += a * b;
    c %= 3;
    System.out.println("a = " + a);
    System.out.println("b = " + b);
    System.out.println("c = " + c);

  }
}

The output of this program is shown here:

a = 2
b = 4
c = 2