Four types and eight types of java

four categories	eight	number of bytes	Data representation range
Integer	byte	1	-128～127
	short	2	-32768～32767
	int	4	-2147483648～2147483648
	long	8	-263～263-1
floating point	float	4	-3.403E38～3.403E38
	double	8	-1.798E308～1.798E308
character type	char	2	Represents a character like ('a', 'A', '0', 'home')
boolean	boolean	1	There are only two values ​​true and false

 

1  package day01;
 2  
3  /* *
 4  * @author mayi
 5  * @date May 1, 2018 4:30:13 PM
 6  * 
 7  * @project_name javaStudy
 8  * @package_name day01
 9  * @file_name Variabe.java
 10  * @description 
 11   */ 
12  public  class Variabe {
 13  //         Define variables in Java
 14  //        Define variables of all data types
 15  //        Four types and eight types 
16          public  static  void main (String[] args) {
 17                 // Define integer type, byte type byte type
 18                  // 1 byte in memory, -128 127 
19                  byte b = 100 ;
 20 System.out                  .println (b);
 21                  
22                  // Define integer type, short integer Type, short type
 23                  // 2 bytes in memory, -32768 32767 
24                  short s = 200 ;
 25 System.out                  .println (s);
 26                  
27                  // Define integer type, integer, int type
 28                  // memory 4 bytes in, -2147483648 2147483647 
29                  int i = 500006 ;
 30System.out                  .println (i);
 31                  
32                  // define integer type, long integer, long type
 33                  // 8 bytes in memory 
34                  long l = 21474836407L ;
 35 System.out                  .println (l);
 36                  
37                  // Define floating-point data, single-precision float type
 38                  // 4 bytes in memory 
39                  float f = 1.0F ;
 40 System.out                  .println (f);
 41                  
42                  
43                  // Define floating-point data, double-precision double Type
 44                  // 8 bytes 
45 in memory                 double d = 2.2 ;
 46 System.out                  .println (d);
 47                  
48                  // Define character type, char
 49                  // 2 bytes in memory, must be wrapped in single quotes, only 1 character can be written 
50                  char c = ' m ' ;
 51 System.out                  .println (c);
 52                  
53                  // Define boolean type, boolean
 54                  // 1 byte in memory, data value, true false 
55                  boolean bool = true ;
 56 System.out                  .println (bool);
57         }
58 }