Hello guys, welcome to lingarajtechhub.com . Today we are going to discuss the given expression by taking user input of 3.14*r^2.
Code:
package com.mul.java; import java.util.Scanner; public class Mul { public static void main(String[] args) { double r; Scanner sc=new Scanner(System.in); System.out.println("Enter the value of r:"); r=sc.nextDouble( ); double p=3.14*r*r; System.out.println("Result="+p); } }
Line-1:
- package com.mul.java
It is a java package , this package is created in a java project and it contains classes inside the package.
Line-2:
- import java.util.Scanner
In java, Scanner is a class. util package used for obtaining the input of the data types like int, double, float , char and strings.
Line-3:
- public class Mul
“Mul” is the class-name , class is a template used to create objects & class-name first letters must be capital. It is public means we can use this outside of the package.
Line-4:
- public static void main(String[] args)
It is a main method in which we can execute a program.
- public : It is an access modifier. The main() is public because we can access main() outside of the class , if main() can’t be public then JVM(Java Virtual Machine) can’t be called main() & code can’t be executed.
- Static : static is a keyword in which the main method has to be static in which JVM can load the class into memory and call the main method without creating an instance.
- Void : Void is a data type. It means no return type.
- main(): Main is a function.
- String [] args : string means collection of characters ,String[] args represents a collection of Strings that are separated by a space and can be typed into the program on the terminal directly.
Line-5:
- double r
Here r is the variable and double is a data type of the variable.
Line-6:
- Scanner sc=new Scanner(System.in)
Scanner is a class and sc is the instance of the object which is the new Scanner . System.in is an argument.
Line-7:
- System.out.println(“Enter the value of r:”)
System is a class name and out is the instance of the system. Println is to print the new line & print the value of r.
Line-8:
- r=sc.nextDouble( )
“r” is a variable that we take and sc is our instance name which is created for an object and nextInt() is a method of a Scanner object that reads in a string of digits or char and converts them into a double type.
Line-9:
- double p=3.14*r*r
Here “p” is a variable where a given question output will be stored and double is the data type.
Line-10:
- System.out.println(“Result=”+p)
System is a predefined class. Out is a static variable of type printstream present in the system class. Println shows the result.