int x = 99;
int y = 10;
y = --x ;
System.out.println("x: " + x + "  y: " + y );

More Assignment Operators

The operators +, -, *, /, (and others) can be can be used with = to make combined operators. For example, the following adds 5 to sum:

sum += 5;        // add 5 to sum

This statement has the same effect as:

sum = sum + 5;   // add 5 to sum

Here is a list of some combined operators. These operators work in three steps. First, the complete expression on the right of the = is evaluated. Second, the operation that is combined with the = is performed. Finally the result is assigned to the variable.

Operator	Operation	Example	Effect
=	assignment	sum = 5;	sum = 5;
+=	addition with assignment	sum += 5;	sum = sum + 5;
-=	subtraction with assignment	sum -= 5;	sum = sum - 5;
*=	multiplication with assignment	sum *= 5;	sum = sum * 5;
/=	division with assignment	sum /= 5;	sum = sum/5;

 

double w = 12.5 ;
double x =  3.0;

w *= x - 1 ;
x -= 1 + 1;

System.out.println( " w is " + w + " x is " + x );