TABLE 2 . 1 :
Java primitive types.
( Type )
( Size )
( Values )
-128 to 127
-32,768 to 32,767
-2,147,483,648 to 2,147,483,647
8 bytes -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807
10 96 to 10 96
10 384 to 10 384
true of false
0 to 65,535
letter. For example, the following code declares, sets, and prints the value of an integer
System. out . println ( i ) ;
The first line declares the variable i to be of type integer. The second line assigns the
number 3 to the variable. The third line prints the value of the variable. The first two lines
can be combined as follows.
Note that several variables can be declared on the same line. For example, the following
is a valid statement.
int i=3, j =4;
However, we can define multiple variables in a single line only when all the variables are
of same type.
Note that a computer is not all powerful, that is, it cannot represent an arbitrary number.
For example, we all know that there are infinitely many real numbers, while the main
memory of a computer is finite. This is why Java defines primitive variable types that take
a fixed amount of memory. For example, the byte type can be used to store a small integer,
while the long type can be used to store up to a 19-digit integer. Most of the time, we want
to store an integer that is not very big (less than 10 digits) and we will use the type int .
Note that most types allow for both negative and positive integers to be stored. Usually,
the first bit of the binary representation of a number indicates if the number is positive or
There is a special syntax that is needed in Java to represent a long number. The letter
“L” must be appended to the end of the number. For example, a variable of a long type
long ssn = 999333222L;
A float and a double must have a decimal point. For example, the number 3 is perceived
as an int , while the number 3.0 is considered a double .A float must also have the letter
F after it. Here is an example of declaring a variable of type float .
float pi = 3.1415F;
A byte is a number that is represented by a single byte (8 bits). A hexadecimal number
can be specified by using the 0x prefix. For example, consider the following code snippet.
System. out . println (x) ;