Getting Started - Java - page 32

Everything we said about the increment operator applies to the decrement operator
as well, except that the value of the variable is decreased by one rather than increased
by one. For example, consider the following code:

decrement
operator

int n = 8;
int valueProduced = n

−− ;
System.out.println(valueProduced);
System.out.println(n);

This produces the output:

8
7

On the other hand, the code

int n = 8;
int valueProduced =

−− n;
System.out.println(valueProduced);
System.out.println(n);

produces the output:

7
7

Both n −− and −− n change the value of n by subtracting one, but they evaluate to dif-
ferent values. n −− evaluates to the value n had before it was decremented; on the other
hand, −− n evaluates to the value n has after it is decremented.
You cannot apply the increment and decrement operators to anything other than a
single variable. Expressions such as (x + y)++ , −− (x + y) , 5++ , and so forth are all ille-
gal in Java.
The use of the increment and decrement operators can be confusing when used inside
of more complicated expressions, and so, we prefer to not use increment or decrement
operators inside of expressions, but to only use them as simple statements, such as:

n++;

Self-Test Exercises
22. What is the output produced by the following lines of program code?

int n = ( int )3.9;
System.out.println("n == " + n);