Core java Programs1

//Hello World Program in Java

public class HelloWorld {

       public static void main(String[] args) {

              System.out.println("Hello  World");

       }

}

public class HelloWorld {

       public static    strictfp void main(String[] args) {

              System.out.println("Hello  World");

       }

      }

public class HelloWorld {

       public static    final void main(String[] args) {

              System.out.println("Hello  World");

       }

     }

public class HelloWorld {

       public static    final void main(String... args) {

              System.out.println("Hello  World");

       }

}

//  Can you have multiple classes in a java source file

public class D {

       public static void main(String[] args) {

              System.out.println("hi");

       }

}

class A

{

      

}

class B

{

      

}

class  C

{

      

}

//Local variable static non  static or instance variables

public class Sample1 {

       int x=12;   //non static

      

       static int y=13;  //static

      

       void m1()

       {

              int k=12; // local

             

       }

public static void main(String[] args) {

       Sample1 s=new Sample1();

       s.m1();

}

}

// Factorial Number

public class Factorial {

      

       static int fact (int num)

       {

              int f=1;

             

              for (int i = 1; i <=num; i++) {

                    

                     f=f*i;

              }

              return f;

             

       }

       public static void main(String[] args) {

              int d= fact(5);

              System.out.println(d);

             

       }

}

//Fibonacci Series

public class Fibonacci {

public static void main(String[] args) {

       int n=10;

       int a=0;

       int b=1;

       int c=1;

for(int i=1;i<=n;i++)

{

        c=a+b;

        a=b;

        b=c;

        c=a;

        System.out.println(c);

}

}

}

O/P:--

1

1

2

3

5

8

13

21

34

55

//Armstrong Number

public class ArmstrongNumber {

public static void main(String[] args) {

       int n=153;

       int r=0;

       int d=n;

       int c=0;

       while(n!=0)

       {

              r=n%10;

              c=c+r*r*r;

              n=n/10;

       }

       if(d==c)

       {

              System.out.println("Armstrong number");

       }

       else

       {

              System.out.println("not a armstrong number ");

                    

             

       }

}

}

O/P:-

Armstrnng number

//Palindrome Number

public class Palindrome {

public static void main(String[] args) {

int n=121;

int r=0;

int d=n;

int rev=0;

while(n!=0)

{

r=n%10;

rev=rev*10+r;

n=n/10;

}

if(d==rev)

{

       System.out.println("palindrome");

}

else

{

       System.out.println("not a palindrome");

}

      

}

}

// swapping 2 Numbers

public class Swapping {

       public static void main(String[] args) {

              int a=50;

              int b=20;

              a=a*b;

              b=a/b;

              a=a/b;

              System.out.println(a);

              System.out.println(b);

       }

}

O/P:   20  50