Page 479 - Introduction to Programming with Java: A Problem Solving Approach

11.5 Prefix/Postfix Modes for Increment/Decrement Operators 445
line#
x
y
output
1
?
?
3
4
4
5
4
5
5
55
6
4
7
4
7
5
8
54
Here’s a review question to help with your debugging skills. What would the outputs have
been if the println arguments had been (x + ' ' + y)? Instead of specifying the the quotes. string version of a space, this would have specified the character version of a space, and
it would make the computer consider the argument to be a mathematical expression rather than a string con- catenation. Since x and y are integers, it would promote the space character to its underlying numeric value, which is 32 (see Figure 11.4). The first print statement would add (5 􏰁 32 􏰁 5) and print 42. The second statement would add (5 􏰁 32 􏰁 4) and print 41.
The decrement operator’s prefix and postfix modes work the same as for the increment operator, but they subtract one instead oAf apddaonge.oTo gePt aDfeFelingEfornhohwathenycwoerk,rtrace this code fragment:
1
int a, b, c;
a = 8;
b = --a;
c = b-- + --a;
System.out.println(a + " " + b + " " + c);
2
3
4
5
6
Pay attention to
line#
a
b
c
output
1
?
?
?
3
8
4
7
4
7
5
6
5
13
5
6
6
6 6 13
Let’s examine line 5 in more depth:
c = b-- + --a;