Combine An Arithmetic Operation With An Assignment Operator

Java provides special operators that can be used to combine an arithmetic operation
with an assignment. As you probably know, statements like the following are quite
common in programming:
a = a + 4;
In Java, you can rewrite this statement as shown here:


a += 4;
This version uses the += assignment operator. 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.
There are assignment operators for all of the arithmetic, binary operators. Thus,
any statement of the form
var = var op expression;
can be rewritten as
var op= expression;
The assignment operators provide two benefits. First, they save you a bit of typing,
because they are “shorthand” for their equivalent long forms. Second, they are
implemented more efficiently by the Java run-time system than are their equivalent
long forms. For these reasons, you will often see the assignment operators used in
professionally written Java programs.
Here is a sample program that shows several op= operator assignments in action:
// Demonstrate several assignment operators.
class OpEquals {
public static void main(String args[]) {
int a = 1;
int b = 2;
int c = 3;
a += 5;
b *= 4;

c += a * b;
c %= 6;
System.out.println("a = " + a);
System.out.println("b = " + b);
System.out.println("c = " + c);
}
}
The output of this program is shown here:
a = 6
b = 8
c = 3