Lession - #84 Java - Basic DataTypes

• Primitive Data Types :

   There are eight primitive datatypes supported by Java. Primitive datatypes are predefined by the language and named by a keyword.Let us look into eight primitive data types in detail.



• byte

  • Byte data type is an 8-bit signed two's complement integer
  • Minimum value is -128 (-2^7>
    
  • Maximum value is 127 (inclusive>
    (2^7 -1>
    
  • Default value is 0
  • Byte data type is used to save space in large arrays, mainly in place of integers, since a byte is four times smaller than an integer.
  • Example: byte a = 100, byte b = -50
  
  

• short

• Short data type is a 16-bit signed two's complement integer
• Minimum value is -32,768 (-2^15>
  
• Maximum value is 32,767 (inclusive>
  (2^15 -1>
  
• Default value is 0
• Short data type can also be used to save memory as byte data type. A short is 2 times smaller than an integer
• Example: short s = 10000, short r = -20000



• int

• Int data type is a 32-bit signed two's complement integer
• Minimum value is -2,147,483,648 (-2^31>
  
• Maximum value is 2,147,483,647 (inclusive>
  (2^31 -1>
  
• Default value is 0
• Integer data type is generally used as the default data type for integral values unless there is a concern about the memory
• Example: int a = 100000, int b = -200000



• long

• Long data type is a 64-bit signed two's complement integer
• Minimum value is -9,223,372,036,854,775,808(-2^63>
  
• Maximum value is 9,223,372,036,854,775,807 (inclusive>
  (2^63 -1>
  
• Default value is 0L
• This type is used when a wider range than int is needed
• Example: int a = 100000, int b = -200000



• float

• Float data type is a single-precision 32-bit IEEE 754 floating point
• Float is mainly used to save memory in large arrays of floating point numbers
• Default value is 0.0f
• Float data type is never used for precise values such as currency
• Example: float f1 = 234.5f



• double

• Double data type is a double-precision 64-bit IEEE 754 floating point
• This data type is generally used as the default data type for decimal values, generally the default choice
• Double data type should never be used for precise values such as currency
• Default value is 0.0d
• Example: double d1 = 123.4



• boolean

• boolean data type represents one bit of information
• There are only two possible values: true and false
• This data type is used for simple flags that track true/false conditions
• Default value is false
• Example: boolean b1=true.



• char

• char data type is a single 16-bit Unicode character
• Minimum value is '\u0000' (or 0>
  
• Maximum value is '\uffff' (or 65,535 inclusive>
  
• Char data type is used to store any character
• Example: char c1='A'.



• Reference Data Types :

• Reference variables are created using defined constructors of the classes. They are used to access the objects. These variables are declared to be of a particular kind that can't be changed. For example, Employee, Puppy, and so on.
• Class objects and different kinds of array variables come under reference datatype.
• Default value of any reference variable is invalid.
• A reference variable can be used to refer any object of the declared type or any compatible type.
• Example : Animal animal = new Animal("giraffe">
  ;

Java Literals :

byte a = 68;
char a = 'A';

int decimal = 100;
int octal = 0144;
int hexa =  0x64;

Example :

"Hello World"
"two\nlines"
"\"This is in quotes\""

char a = '\u0001';
String a = "\u0001";