Beginners for JAVA language

 Basics of java programming:

To write a java program, the following details, are need.

1. Command-line:

• It describes what's going on inside a program, so that person looking at the source code does not have a hard time figuring it out.
• That means human understanding and not be execute in output.
• Types of comments:

    (i) Single line comments:

     Syntax:

                 //Statements or Comment 

    (ii) Multiline comments or comments for combined in multi line:

     Syntax:

                  /* comment */

                  /** comment */

2.Variables:

• A variable is nothing but it allocates the memory space and holds the values.
• That means every memory of address is difficult to use in the program, conversely, we give that address as a simple user-defined word or character is called variable.

• For example, each user dials the call using a contact name only not use the phone number. i.e. each user needs an easy way to access the phone number to make a call to others.

• Here, the phone number act as a memory address and saved details of contacts called variables(this process happens in CPU).

         Syntax:

                     Data_type variable_name;

         Example:

                     int x, y;

Rules for naming the variables:

• The first character must be an alphabet or an underscore(_).
• No commas or blank spaces are allowed within a variable name.
• No special symbols, an underscore can be used in a variable name.

Scope of variables:

• It implies the availability of variables within the program.
• It is divided into two types.

     (i) Local variable:

• The variables which are defined inside the function block called a local variable.

         Example:

                       public static void main (String args[])

                      {

                              int a,b;//local variable

                              ......

                       }

     (ii) Global variable:

• The variables that are declared before the main() a function is called a global variable.

         Example:

                      int a,b;//Global variable

                      public static void main (String args[])

                     {

                             ......

                      }

3.Data types:

• The data type is the type or kind of data, that is going to process within the program. 

    Pre-defined data type:

• The most widely used data types are

 4. Input function:

• This function is used to get value from users.

        Syntax:

                      Scanner object_name= new Scanner(System.in);

                      variable_name= scanner_object_name.input_type();

5. Input type:

•  It is used to indicate unknown value for types to display on the output screen and also get value from the user. ( i.e. Holds unknown values).

There are,  

6.Output function: 

• This function is used to show details on the output screen for user understanding.

         Syntax:

                    System.out.println("Statement");          

7.Escape sequence: 

• This is used to align output on the screen.

Example program:

1. // Write a program to add two number and value get from user.

   package exampleprogram;

   import java.util.Scanner;

   public class Exampleprogram {

       public static void main(String[] args) {

          Scanner input = new Scanner(System.in);

          int a,b;

          System.out.println("\t\t  Additions of two number.... ");

          System.out.println("\nEnter two value  : ");

          a = input.nextInt();

          b = input.nextInt();

          int c=a+b;

          System.out.println("Additions of a and b value is : "+c);

       }

   }

Output:

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