Chapter 2 Elementary Programming
1. Valid identifiers: applet, Applet, $4, apps
Invalid identifiers: a++, --a, 4#R, #44
2. Keywords:
class, public, int
3. double miles = 100;
final double MILE_TO_KILOMETER = 1.609;
double kilometer = MILE_TO_KILOMETER * miles;
System.out.println(kilometer);
The value of kilometer is 160.9.
4. There are three benefits of using constants: (1)
you don’t have to repeatedly type the same value; (2)
the value can be changed in a single location, if
necessary; (3) the program is easy to read.
final int SIZE = 20;
5.
a = 46 / 9; => a = 5
a = 46 % 9 + 4 * 4 - 2; => a = 1 + 16 – 2 = 15
a = 45 + 43 % 5 * (23 * 3 % 2); => a = 45 + 3 * (1) = 48
a %= 3 / a + 3; => a %= 3 + 3; a % = 6 => a = a % 6 = 1;
d = 4 + d * d + 4; => 4 + 1.0 + 4 = 9.0
d += 1.5 * 3 + (++a); => d += 4.5 + 2; d += 6.5; => d = 7.5
d -= 1.5 * 3 + a++; => d -= 4.5 + 1; => d = 1 – 5.5 = -4.5
6.
2
2
-4
-4
0
1
7. For byte, from -128 to 127, inclusive.
For short, from -32768 to 32767, inclusive.
