Question

can i get an example of a simple code using the following picture in java

20% Basic Java usage of comments next to the program variables declaration: input/output data types

Answer 1

package abc;
import java.util.*;//import statements for importing the packages
class MySite//main class as it contains main method
{//start of main class
        public static void main(String args[])//main method
        {//start of main method
                Scanner sc=new Scanner(System.in);//scanner class used to give user input at the run time
                int a,b,sum;//declaration of integer type variables
                float c,d,diff;//declaration of float type variables
                System.out.println("enter values of a and b");//prints whatever written in double quote to the output screen
                a=sc.nextInt();//method to assign user input integer value to "a" at run time
                b=sc.nextInt();//method to assign user input integer value to "b" at run time
                sum=a+b;//adds the value of a and b and stores the value in sum
                System.out.println(sum);//prints the values of sum to the output screen
                System.out.println("enter values of c and d");
                c=sc.nextFloat();//method to assign user input floating type value to c at run time
                d=sc.nextFloat();//method to assign user input floating type value to d at run time
                diff=c-d;//calculate the difference between c and d and stores it in the diff.
                System.out.println(diff);//prints the value of "diff" to output;
        }//end of the main method
}//end of main class

JAVA COMMENTS:

In java comments are used to explain the codes and to make it more understandable to the person who executes/reads the code.

comments are of two types in java :

single line comments
multi line comments

SINGLE LINE COMMENTS:

Single-line comments start with two forward slashes (//).

The text between // and the end of the line will not be executed by Java

MULTI LINE COMMENTS:

always multi line comments start with /* and ends with */.

text between /* and */ will not be executed by Java program.

JAVA VARIABLES:

In java variables are used for the storing of the data.

The variable may of any type like

Intergers
floating points
strings
JAVA DATA TYPES:

Data types are of two types in java

Primitive data types
Non-Primitive data types

PRIMITIVE DATA TYPES:

A data type which specifies the size and type of variable values and it has no additional method.

there are 8 primitive data types

byte
short
int
long
float
double
boolean
char

NON-PRIMITIVE DATA TYPES:

Non-primitive types are created by the programmer and is not defined by Java (except for String).Non-primitive data types refer to the objects so they are called reference types in java .These types can be used to perform certain operations and to call some methods.

some of non primitive data types are

Strings
Arrays
Classes
Interface