9. Variable types And Characteristics .

 Variable Types

1) Global Variable - Global Variable are declared in class block are known as Global Variable.

They are classified as 2 types : -

                                             1) static Variable

                                             2) Non-Static Variable

2) Local Variable - The Variable which are declared in method block inside method block expect class block called as local variable.

Characteristic of local variable - 

1)  Variable declared inside a block remain accessible to that block only cannot accessible from outside the block.

If we accessed it from outside block,  it will get compile time error. 

ex - class example

          {

               public static void main (String [] args )

                  {

                       int a = 20 ;

                       System.out.println(a) ;    // output = 20

                   }

                 System.out.println(a) ;             // This will give you compile time error

            }  // Method block close

         }  // Class block close .

2)  We cannot create more than one variable of same name in same method block we can have same name variable in different block.

ex 1  -  class example2

           {

               public static void main (String [] args )

                  {

                       int a = 20 ;

                       System.out.println(a) ;

                       string a = "hello" ;

                       System.out.println(a) ;

                  }

            }

  // output  -   we cannot find symbol a  ;

  ex 2 -   class example3

           {

               public static void main (String [] args )

                  {

                      {

                       int a = 20 ;

                       System.out.println(a) ;

                       }

                      {

                      int a = 30 ;

                     System.out.println(a) ;

                      }

                  }

            }  

//  Output  is 10 20 .

3)  We cannot use local variable without initialization because local variable is not assigned with default value as a programmer, we have to assign same value to local variable and then use it.

ex - class var

   {

      public static void main (String [] args )

        {

           char ch ;

            System.out.println(ch) ;

        }

   }

// Output compile time error (CTE).