Understanding basic data types and reference data types

Six types of numbers (four integers, two floating-point types), one character type, and one Boolean type.

byte:
The byte data type is a 8-bit, signed, integer in binary complement notation;
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.

Short:
The short data type is a 16-bit, signed integer with a binary complement representation
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.

int:
The int data type is a 32-bit, signed integer with a binary complement representation;
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 with a binary complement representation;
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.

Float:
The float data type is a single-precision, 32-bit, IEEE 754 compliant floating-point number;
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.

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 0.0f;
Example: Double D1 = 123.4.

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;
The minimum value is ' \u0000 ' (that is, 0);
The maximum value is ' \uffff ' (that is, 65,535);
Char data type can store any character;
Example: char letter = ' A '.

Understanding basic data types and reference data types