Java Basic data types

Int

• The int data type is a 32-bit, signed integer represented by twos complement; 3 bytes
• The minimum value is-2,147,483,648 ( -2^31);
• The maximum value is 2,147,485,647 (2^31-1);
• The generic integer variable defaults to the int type;
• The default value is 0;
• Example: int a = 100000, int b =-200000.

Long

• The Long data type is a 64-bit, signed integer in binary complement; 4 bytes
• The minimum value is-9,223,372,036,854,775,808 ( -2^63);
• The maximum value is 9,223,372,036,854,775,807 (2^63-1);
• This type is mainly used on systems that need to compare large integers;
• The default value is 0L;
• Example: Long a = 100000l,int B = -200000l.

Short

• The short data type is a 16-bit, signed integer in twos complement, representing 2 bytes
• The minimum value is-32768 ( -2^15);
• The maximum value is 32767 (2^15-1);
• The short data type can also save space as Byte. A short variable is one-second of the space occupied by the int variable;
• The default value is 0;
• Example: Short s = 1000,short r =-20000.

Float

• The float data type is single-precision, 32-bit, IEEE 754 compliant floating-point number, 4 bytes -3.4*e38-3.4*e38 ... A floating-point number is a rounding error
• Float saves memory space when storing large floating-point groups;
• The default value is 0.0f;
• Floating-point numbers cannot be used to denote precise values, such as currency;
• Example: float f1 = 234.5f.
• Float f=6.26 (Error floating point number default type is double type)
• Float f=6.26f (convert right, force)
• Double d=4.55 (correct)

Boolean

• The Boolean data type represents one bit of information;
• Only two values: true and false;
• This type is only used as a sign to record the true/false situation;
• The default value is false;
• Example: Boolean one = True.

Char

• The char type is a single 16-bit Unicode character, and a character is represented with ' '. The Unicode character set is used inside Java: He has some escape characters, 2 bytes
• The minimum value is ' \u0000 ' (that is, 0);
• The maximum value is ' \uffff ' (that is, 65,535); can be used as an integer, each of its characters corresponds to a number

Byte

• The byte data type is a 8-bit, signed, integer represented by twos complement; (256 digits), 1 bytes
• The minimum value is-128 ( -2^7);
• The maximum value is 127 (2^7-1);
• The default value is 0;
• The byte type is used to save space in large arrays, mainly in place of integers, because the byte variable occupies only one-fourth of the int type;
• Example: Byte a = 100,byte B =-50.

Double

• The double data type is a dual-precision, 64-bit, IEEE 754-compliant floating-point number;
• The default type of floating-point number is double type;
• A double type cannot also represent an exact value, such as a currency;
• The default value is 0.0d;
• Example: Double D1 = 123.4.

Java Basic data types