Data types in java

Data types

Their memory, data types ranges, their default values, variable declaration, initialization, type casting and conversions using wrapper classes:

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Is Java datatypes are signed datatypes or unsigned datatypes?

Signed datatypes: 

C, C++ supports ASCII range characters char ch='A';

Java supports Unicode range characters char ch='A';

Primitive data types:

Numeric data types:

   1. Integer type data types

  byte - 1 byte - (-128 to +127),  0

  short - 2 bytes - (-32768 to +32767), 0

  int - 4 bytes - (-2147483648 to +2147483647), 0

  long - 8 bytes, -9,223,372,036,854,775,808 .. 9,223,372,036,854,775,807

  

  2.  floating point data types

  float - 4 bytes - (-3.402823E38 to +3.402823E38), 0.0f

  double - 8 bytes - (-1.79769313486232E308 to +1.79769313486232E308), 0.0d

Character data type:

   char - 2 bytes, 0-255 (ASCII), 0-255,256-65535 - 65536 (Unicode), \u000

   char ch='a'; 'A'  '0'  'Σ'

   97   65   48   228

   String frml="πΣ¥Ω"

   

   For ASCII range characters in case of language supporting ASCII range chars:

   char ch='~'; 126

   char ch='¥'; 157 instead -108

   

   For ASCII range characters in case of language supporting Unicode range chars:

   char ch='~'; 126

   char ch='¥'; 157

Boolean data type

   Boolean - 1 byte, (true/false), false

Secondary data types:

   arrays - int i[]=new int[10]; i[0]=1; i[9]=10; int j[]={1,2,3,4,5};

   classes - class Emp {}, class Student {}, class Customer {}

   

// DataTypeRangeTest.java

public class DataTypeRangeTest {

  public static void main(String rags[])  {

      // byte b=-128b; // valid

      // byte b=-129;// compilation error, possible loss of precision

      // byte b=127B;

      // byte b=128;

      byte b=127b;

      byte b1=127B;

      short s=-32768s;

      short s1=32767S;

      int i=-2147483648i;

      // int i1=2147483648; // integer number too large

      int i1=2147483647I; 

      // all integer literals are by default treated as int hence long value must suffix with l or L

      long l=-2147483649L;

      long l1=2147483648L;

      float f=-3.402823E38F;

      float f1=+3.402823E38f;

      // all floating point literals are by default treated as double hence float value must suffix with f or F

      double d=-1.79769313486232E307d;

      double d1=1.79769313486232E307D;

      char ch='A';

      char ch1=65;

  boolean boo=true;

  }

}