Java data type, java Basic Data Type

Java data type, java Basic Data Type

1. Basic types: 8

Number: INTEGER: byte 1 byte (-128 to 127) one byte occupies 8 bits 1bit =

Short: 2-byte short integer

Int: integer 4 bytes

Long: 8-byte long integer

Float: 4-byte float: * 7 digits

Double: double Floating Point type, 8 bytes // ******* valid number sixteen

Non-numeric type: boolean indicates the logical type. Values true and false are false.

Character Type: char: represents A single character, 1 byte, and the value is included in ''. For example, 'male' '1', 'A', A single Chinese character, letter, and number are supported.

2. reference types: Three

Class type (Packaging class (String is a special packaging type), custom type, JDK built-in class)

Interface Type

Array type

Enumeration type

3. type conversion:

Automatic conversion: the type with low precision can be automatically converted to a type with high precision.

Forced conversion: converts a type with high precision to a type with low precision to a forced conversion with a loss of precision.

4. in java, common data types range from small to large (precision from high to low): byte <short <char <int <float <double.

5. Forced conversion of data types:

1). the string type and int or long type are converted according to the ASCII code table.

Syntax format (char) 97; (int) 'A'; (long) 'B ';

(The lowercase letter range is 97-122, and the upper-case letter range is 65-90)

2). Small-to-large conversion between numeric models, automatic conversion, large-to-small conversion, forced conversion