A basic program that gets input x (Base) and y (Power/Exponent) from the user and prints x^y.

By this program, you can understand the usage of commandline arguments, use of arithmetic operators, printing variables and more.

Task: Print the value of x^y ...

  Eg: x, base = 2
      y, power = 5
  Final Output: 
      2 ^ 5 = 32.0
          
  Eg: x, base = 50
      y, power = 5
  Final Output:
      50 ^ 5 = 3.125E8
         

The filename must have the same name as the public class name, This is to ensure that the Java Virtual Machine (JVM) understands the entry point of the program

To run the program, open your commandline and type the following:

• Without Commandline Arguments

 $ ..\JavaBasic> javac .\Power\Power.java
 $ ..\JavaBasic> java Power.Power

• Defined Arguments

 -> argument-1: 
      name: x (base)
      type: integer
      help: Used to specify the base value.
  
 -> argument-2:
      name: y (power)
      type: integer
      help: Used to specify the power or exponent value.  

• With Commandline Arguments

 $ ..\JavaBasic> javac .\Power\Power.java
 $ ..\JavaBasic> java Power.Power 2 5

package Power;

import java.util.Scanner;

public class Power {
    static int x, y;

    public static void main(String[] args) {
        if (args.length > 0) {
            if (args.length == 2) {
                x = Integer.parseInt(args[0]);
                y = Integer.parseInt(args[1]);
                System.out.println(" " + x + " ^ " + y + " = " + Math.pow(x, y));
            } else
                System.out.println(" [!] Commandline Arguments must be two integers: [x (base)], [y (power)]");
        }

        Scanner scanner = new Scanner(System.in);
        System.out.print(" [<-] Enter the base integer value: ");
        int x = scanner.nextInt();
        System.out.print(" [<-] Enter the exponent integer value: ");
        int y = scanner.nextInt();
        scanner.close(); // closing the stream as it's not needed anymore.
        System.out.println("[->] " + x + " ^ " + y + " = " + Math.pow(x, y));
    }
}

import java.util.Scanner; : imports Scanner class from java > util package. Scanner is a class that lets you get input form the user. Scanner can take any primitive data type as input from the user.

public static void main(String[] args) : main method/function is the first method that will be executed in any java programs.

String[] args : args is a array of String type. It is used to get commandline arguments for your program.

args.length > 0 : checks whether args is empty or not

System.out.println(); : Prints the String and changes output cursor to next line

Scanner scan = new Scanner ( System.in ); : scan is an object(a special variable that stores the address in RAM/main memory) of the class Scanner. Here scan acts as the variable that has the access to System.in stream (An input stream that connects keyboard input to the program.

scan.nextInt() : gets Integer input from user.

scan.close(); : closes the input stream link/pipe.

Math.pow(base, exponent) : A predefined method to find the power of a number.