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By Mahesh biradar

Read Number from Console and Check if it is a Palindrome Number

/*
  Read Number from Console and Check if it is a Palindrome Number
  This Java example shows how to input the number from console and
  check if the number is a palindrome number or not.
 */

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class InputPalindromeNumberExample {

 public static void main(String[] args) {

  System.out.println("Enter the number to check..");
  int number = 0;

  try
  { 
   //take input from console
   BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
   //parse the line into int
   number = Integer.parseInt(br.readLine());

  }
  catch(NumberFormatException ne)
  {
   System.out.println("Invalid input: " + ne);
   System.exit(0);
  }
  catch(IOException ioe)
  {
   System.out.println("I/O Error: " + ioe);
   System.exit(0);
  }

  System.out.println("Number is " + number);
  int n = number;
  int reversedNumber  = 0;
  int temp=0;

  //reverse the number
  while(n > 0){
   temp = n % 10;
   n = n / 10;
   reversedNumber = reversedNumber * 10 + temp;
  }

  /*
   * if the number and it's reversed number are same, the number is a 
   * palindrome number
   */
  if(number == reversedNumber)
   System.out.println(number + " is a palindrome number");
  else 
   System.out.println(number + " is not a palindrome number");
  }

}

/*
Output of the program would be
Enter the number to check..
121
Number is 121
121 is a palindrome number
*/

prime numbers java

/*
  Prime Numbers Java Example
  This Prime Numbers Java example shows how to generate prime numbers
  between 1 and given number using for loop.
 */

public class GeneratePrimeNumbersExample {

 public static void main(String[] args) {

  //define limit
  int limit = 100;

  System.out.println("Prime numbers between 1 and " + limit);

  //loop through the numbers one by one
  for(int i=1; i < 100; i++){

   boolean isPrime = true;

   //check to see if the number is prime
   for(int j=2; j < i ; j++){

    if(i % j == 0){
     isPrime = false;
     break;
    }
   }
   // print the number 
   if(isPrime)
    System.out.print(i + " ");
  }
 }
}

/*
Output of Prime Numbers example would be
Prime numbers between 1 and 100
1 2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97
*/

list Odd numbers java

/*
	List Odd Numbers Java Example
	This List Odd Numbers Java Example shows how to find and list odd
	numbers between 1 and any given number.
*/
 
public class ListOddNumbers {
 
	public static void main(String[] args) {
 
		//define the limit
		int limit = 50;
 
		System.out.println("Printing Odd numbers between 1 and " + limit);
 
		for(int i=1; i <= limit; i++){
 
			//if the number is not divisible by 2 then it is odd
			if( i % 2 != 0){
				System.out.print(i + " ");
			}
		}
	}
}
 
/*
Output of List Odd Numbers Java Example would be
Printing Odd numbers between 1 and 50
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 
*/

List Even Numbers Java

/*
	List Even Numbers Java Example
	This List Even Numbers Java Example shows how to find and list even
	numbers between 1 and any given number.
*/
 
public class ListEvenNumbers {
 
	public static void main(String[] args) {
 
		//define limit
		int limit = 50;
 
		System.out.println("Printing Even numbers between 1 and " + limit);
 
		for(int i=1; i <= limit; i++){
 
			// if the number is divisible by 2 then it is even
			if( i % 2 == 0){
				System.out.print(i + " ");
			}
		}
	}
}
 
/*
Output of List Even Numbers Java Example would be
Printing Even numbers between 1 and 50
2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 
*/

Java Pyramid

/*
	Java Pyramid Example
	This Java Pyramid example shows how to generate pyramid or triangle like
	given below using for loop.
 
	*
	**
	***
	****
	*****
*/
 
public class JavaPyramid1 {
 
	public static void main(String[] args) {
 
		for(int i=1; i<= 5 ;i++){
 
			for(int j=0; j < i; j++){
				System.out.print("*");
			}
 
			//generate a new line
			System.out.println("");
		}
	}
}
 
/*
Output of the above program would be
*
**
***
****
*****
*/

Java Palindrome Number

/*
	Java Palindrome Number Example
	This Java Palindrome Number Example shows how to find if the given
	number is palindrome number or not.
*/
 
 
public class JavaPalindromeNumberExample {
 
	public static void main(String[] args) {
 
		//array of numbers to be checked
		int numbers[] = new int[]{121,13,34,11,22,54};
 
		//iterate through the numbers
		for(int i=0; i < numbers.length; i++){
 
			int number = numbers[i];
			int reversedNumber  = 0;
			int temp=0;
 
			/*
			 * If the number is equal to it's reversed number, then
			 * the given number is a palindrome number.
			 * 
			 * For example, 121 is a palindrome number while 12 is not.
			 */
 
			//reverse the number
			while(number > 0){
				temp = number % 10;
				number = number / 10;
				reversedNumber = reversedNumber * 10 + temp;
			}
 
			if(numbers[i] == reversedNumber)
				System.out.println(numbers[i] + " is a palindrome number");
			else 
				System.out.println(numbers[i] + " is not a palindrome number");
		}
 
	}
}
 
/*
Output of Java Palindrome Number Example would be
121 is a palindrome number
13 is not a palindrome number
34 is not a palindrome number
11 is a palindrome number
22 is a palindrome number
54 is not a palindrome number
*/

Infinite For loop

/*
  Infinite For loop Example
  This Java Example shows how to create a for loop that runs infinite times
  in Java program. It happens when the loop condition is always evaluated as true.
*/
 
public class InfiniteForLoop {
 
  public static void main(String[] args) {
 
    /*
  * Its perfectely legal to skip any of the 3 parts of the for loop.
  * Below given for loop will run infinite times.
  */
     for(;;)
       System.out.println("Hello");
 
     /*
  * To terminate this program press ctrl + c in the console.
  */
  }
}
 
/*
Output would be
Hello
Hello
Hello
Hello
..
..
*/

Generate Pyramid For a Given Number

/*
	Generate Pyramid For a Given Number Example
	This Java example shows how to generate a pyramid of numbers for given
	number using for loop example.
*/
 
import java.io.BufferedReader;
import java.io.InputStreamReader;
 
public class GeneratePyramidExample {
 
	public static void main (String[] args) throws Exception{
 
		BufferedReader keyboard = new BufferedReader (new InputStreamReader (System.in));
 
		System.out.println("Enter Number:");
		int as= Integer.parseInt (keyboard.readLine());
		System.out.println("Enter X:");
		int x=   Integer.parseInt (keyboard.readLine());
 
		int y = 0;
 
		for(int i=0; i<= as ;i++){
 
			for(int j=1; j <= i ; j++){
				System.out.print(y + "\t");
				y = y + x;
			}
 
			System.out.println("");
		}
	}
}
 
/*
Output of this example would be
 
Enter Number:
5
Enter X:
1
 
0	
1	2	
3	4	5	
6	7	8	9	
10	11	12	13	14
 
----------------------------------------------
 
Enter Number:
5
Enter X:
2
 
0	
2	4	
6	8	10	
12	14	16	18	
20	22	24	26	28
 
----------------------------------------------
 
Enter Number:
5
Enter X:
3
 
0	
3	6	
9	12	15	
18	21	24	27	
30	33	36	39	42
*/

Fibonacci Series Java

/*
	Fibonacci Series Java Example
	This Fibonacci Series Java Example shows how to create and print
	Fibonacci Series using Java.
*/
 
public class JavaFibonacciSeriesExample {
 
	public static void main(String[] args) {
 
		//number of elements to generate in a series
		int limit = 20;
 
		long[] series = new long[limit];
 
		//create first 2 series elements
		series[0] = 0;
		series[1] = 1;
 
		//create the Fibonacci series and store it in an array
		for(int i=2; i < limit; i++){
			series[i] = series[i-1] + series[i-2];
		}
 
		//print the Fibonacci series numbers
 
		System.out.println("Fibonacci Series upto " + limit);
		for(int i=0; i< limit; i++){
			System.out.print(series[i] + " ");
		}
	}
}
 
/*
Output of the Fibonacci Series Java Example would be
Fibonacci Series upto 20
0 1 1 2 3 5 8 13 21 34 55 89 144 233 377 610 987 1597 2584 4181 
*/

multiple variables in for loop

/*
  Declare multiple variables in for loop Example
  This Java Example shows how to declare multiple variables in Java For loop using
  declaration block.
*/
 
public class DeclaringMultipleVariablesInForLoopExample {
 
  public static void main(String[] args) {
 
    /*
  * Multiple variables can be declared in declaration block of for loop.
  */
 
     for(int i=0, j=1, k=2 ; i<5 ; i++)
       System.out.println("I : " + i + ",j : "+ j + ", k : " + k);
 
     /*
  * Please note that the variables which are declared, should be of same type
  * as in this example int.
  */  
 
      //THIS WILL NOT COMPILE
      //for(int i=0, float j; i < 5; i++);
  }
}

multiple variables in for loop

/*
  Declare multiple variables in for loop Example
  This Java Example shows how to declare multiple variables in Java For loop using
  declaration block.
*/
 
public class DeclaringMultipleVariablesInForLoopExample {
 
  public static void main(String[] args) {
 
    /*
  * Multiple variables can be declared in declaration block of for loop.
  */
 
     for(int i=0, j=1, k=2 ; i<5 ; i++)
       System.out.println("I : " + i + ",j : "+ j + ", k : " + k);
 
     /*
  * Please note that the variables which are declared, should be of same type
  * as in this example int.
  */  
 
      //THIS WILL NOT COMPILE
      //for(int i=0, float j; i < 5; i++);
  }
}

Calculate Average value of Array elements using Java

/*
	Calculate Average value of Array elements using Java Example
	This Java Example shows how to calculate average value of array
	elements.
*/
public class CalculateArrayAverageExample {
 
	public static void main(String[] args) {
 
		//define an array
		int[] numbers = new int[]{10,20,15,25,16,60,100};
 
		/*
		 * Average value of array elements would be
		 * sum of all elements/total number of elements
		 */
 
		//calculate sum of all array elements
		int sum = 0;
 
		for(int i=0; i < numbers.length ; i++)
			sum = sum + numbers[i];
 
		//calculate average value
		double average = sum / numbers.length;
 
		System.out.println("Average value of array elements is : " + average);
	}
}
 
/*
Output of Calculate Average value of Array elements using Java Example would be
Average value of array elements is : 35.0
*/