ELEMENTARY PROGRAMMING - Introduction to Java Programming: Comprehensive Version - page 45

T ABLE 2.1

Numeric Data Types

Name Range Storage Size

8-bit signed

byte

- 2 7 to 2 7

byte type

- 1( - 128 to 127)

short 16-bit signed

- 2 15 to 2 15

short type

- 1( - 32768 to 32767)

int 32-bit signed

- 2 31 to 2 31

int type

- 1( - 2147483648 to 2147483647)

long 64-bit signed

2 63 to 2 63

long type

- - 1

(i.e., - 9223372036854775808 to 9223372036854775807)

Negative range: - 3.4028235E + 38 to - 1.4E - 45 32-bit IEEE 754

float

float type

Positive range: 1.4E - 45 to 3.4028235E + 38

double Negative range: - 1.7976931348623157E + 308 to 64-bit IEEE 754 double type

- -

4.9E 324

Positive range: 4.9E - 324 to 1.7976931348623157E + 308

Note
IEEE 754 is a standard approved by the Institute of Electrical and Electronics Engineers
for representing floating-point numbers on computers. The standard has been widely
adopted. Java uses the 32-bit IEEE 754 for the float type and the 64-bit IEEE 754
for the double type. The IEEE 754 standard also defines special floating-point values,
which are listed in Appendix E.

Java uses four types for integers: byte , short , int , and long . Choose the type that is
most appropriate for your variable. For example, if you know an integer stored in a variable
is within a range of a byte, declare the variable as a byte . For simplicity and consistency, we
will use int for integers most of the time in this topic.
Java uses two types for floating-point numbers: float and double . The double type
is twice as big as float , so the double is known as double precision and float as single
precision. Normally, you should use the double type, because it is more accurate than the
float type.

integer types

floating-point types

2.9.2 Reading Numbers from the Keyboard
You know how to use the nextDouble() method in the Scanner class to read a double
value from the keyboard. You can also use the methods listed in Table 2.2 to read a number
of the byte , short , int , long , and float type.

T ABLE 2.2

Methods for Scanner Objects

Method Description

nextByte() reads an integer of the byte type.

nextShort() reads an integer of the short type.

nextInt() reads an integer of the int type.

nextLong() reads an integer of the long type.

nextFloat() reads a number of the float type.

nextDouble() reads a number of the double type.