JavaNumbers

Numbers

Primitive number types are divided into two groups:

Integer types stores whole numbers, positive or negative (such as 123 or -456), without decimals. Valid types arebyte,short,int andlong. Which type you should use, depends on the numeric value.

Floating point types represents numbers with a fractional part, containing one or more decimals. There are two types:float anddouble.

Integer Types

Byte

Thebyte data type can store whole numbers from -128 to 127. This can be used instead ofint or other integer types to save memory when you are certain that the value will be within -128 and 127:

byte myNum = 100;System.out.println(myNum);

Short

Theshort data type can store whole numbers from -32768 to 32767:

short myNum = 5000;System.out.println(myNum);

Int

Theint data type can store whole numbers from -2147483648 to 2147483647. In general, and in our tutorial, theint data type is the preferred data type when we create variables with a numeric value.

int myNum = 100000;System.out.println(myNum);

Long

Thelong data type can store whole numbers from -9223372036854775808 to 9223372036854775807. This is used when int is not large enough to store the value. Note that you should end the value with an "L":

long myNum = 15000000000L;System.out.println(myNum);

Floating Point Types

You should use a floating point type whenever you need a number with a decimal, such as 9.99 or 3.14515.

Thefloat anddouble data types can store fractional numbers. Note that you should end the value with an "f" for floats and "d" for doubles:

float myNum = 5.75f;System.out.println(myNum);

double myNum = 19.99d;System.out.println(myNum);

Scientific Numbers

A floating point number can also be a scientific number with an "e" to indicate the power of 10:

float f1 = 35e3f;double d1 = 12E4d;System.out.println(f1);System.out.println(d1);