Java Reference
In-Depth Information
Note Beginning with Java 8, some changes have been introduced. The data
type int can also be used to define an unsigned integer from 0 to 2 32 -1. The
data type long can be used to define an unsigned integer between 0 and 2 64 -
1. If your application doesn't require negative values, this will offer you a larger
range of valid positive numbers.
You may think that strings (such as name = "Bart Baesens") are lacking in Table 2-6. In fact, as
we will discuss later, Java does not have a built-in string type. It offers special facilities to work with
strings. Note that the default value for the long data type is 0L . The L stands for long and is capital-
ized to avoid confusion with the number one ( l versus 1 ). Likewise, the default values for float and
double end with f and d , respectively.
It is important to define each variable using the appropriate data type. In fact, limiting the range
of a variable can serve as very useful documentation to better understand its meaning during code
inspection and/or maintenance. Furthermore, it can also help save memory if a variable is defined as
byte instead of int (since byte is four times smaller than int ).
literals
A literal is a value assigned to a variable of a specific type. An example of this is:
weight = 60;
height = 1.70;
In this example, the equals sign ( = ) is used as an assignment operator to assign the literals 60 and
1.70 to the variables weight and height , respectively.
Here are some other examples of literals:
boolean overweight = true;
short age = 38;
character initial = 'B';
Note that literals of type long , float , and double can end with the letters L / l , F / f , and D / d ,
respectively. Floating point literals can also be expressed in scientific notation using E or e . This
is illustrated here:
Double bmi = 24.2;
Double bmi = 24.2d;
Float bmi = 0.242e2;
Character literals ( char ) are always enclosed in single quotes and may contain any Unicode charac-
ter (see www.unicode.org for more details). An example of this is as follows:
char gbPoundUniSymbol = '\u00A3';
char gbPoundSymbol = '£';
char dollarUniSymbol = '\u0024';
char dollarSymbol = '$';
 
Search WWH ::




Custom Search