153= 1^3+5^3+3^3

5 mins some important call came

2 mins please
==============================

153%10 =3
153/10 = 15

fetch the last digit
cube the digit
add that cube to the sum
remove the last digit

you need to do to process till my n not equal to 0
=================================
public class Sample {

	public static void main(String[] args) throws NumberFormatException, IOException {
		
		Scanner scan=new Scanner(System.in);
		int n=scan.nextInt();
		int sum=0;
		int temp=n;
		//1234
		while(n!=0) {
			int rem=n%10;
			sum=sum+rem*rem*rem;
			n=n/10;
		}
		if(temp==sum) {
			System.out.println("Armstrong Number");
		}else {
			System.out.println("Not Armstrong");
		}
		
	}

}
=====================================================
Prime number : a number having factors 1 and itself is called prime number
n= Its having 2 factors

n (1 to n)

n=23

1 2 3 .................23
calculate count of number of factors
count==2
its a prime number
=================================================
n= 2 lakh

2 to n/2
if you find atleast one factor you can break the loop

50

2 to 25

=====================================
35

2   17
====================================

100

50

after 50 can you find

===================
24

12 
=================================================
package basic;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Scanner;
//Prime number

public class Sample {

	public static void main(String[] args) throws NumberFormatException, IOException {
		
		Scanner scan=new Scanner(System.in);
		int n=scan.nextInt();
		int count=0;
		for(int i=2;i<=n/2;i++) {
			if(n%i==0) {
				count++;
				break;
			}
				
		}
		if(count==1) {
			System.out.println("Its not a prime number");
		}else {
			System.out.println("Its  a Prime number");
		}
		
	}

}
=====================================================================
1 lakh to 50k 
Scanner scan=new Scanner(System.in);
		int n=scan.nextInt();
		int count=0;
		for(int i=2;i<=(int)Math.sqrt(n);i++) {
			if(n%i==0) {
				count++;
				break;
			}	
		}
		if(count==1) {
			System.out.println("Its not a prime number");
		}else {
			System.out.println("Its  a Prime number");
		}
==================================================================
n=5

*****
*****
*****
*****
*****

we need 

Vars, ifelse , for , nested for , arrays , strings , collections 
=====================================================================
package basic;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Scanner;
//Prime number

public class Sample {

	public static void main(String[] args) throws NumberFormatException, IOException {
		
		Scanner scan=new Scanner(System.in);
		int n=scan.nextInt();
		int count=0;
		for(int i=1;i<=n;i++) {
			for(int j=1;j<=n;j++) {
				System.out.print("*");
			}
			System.out.println();
		}
		
	}

}
====================================================
1 1 1 1 1
2 2 2 2 2
3 3 3 3 3
4 4 4 4 4
5 5 5 5 5
==================================================
package basic;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Scanner;
//Prime number

public class Sample {

	public static void main(String[] args) throws NumberFormatException, IOException {
		
		Scanner scan=new Scanner(System.in);
		int n=scan.nextInt();
		int count=0;
		for(int i=1;i<=n;i++) {
			for(int j=1;j<=n;j++) {
				System.out.print(i+" ");
			}
			System.out.println();
		}
		
	}

}
======================================================