Palindrome program in java

Check given number is palindrome or not

If we reverse a number, that reverse number and original number (given number) both are equal then that number is palindrome number.

Example:

Given number is 121

After reverse the above number, we get 121

Given number and reverse numbers are equal so 121 is palindrome

123 is not palindrome because, 123 reverse is 321 so both are not equal

 

import java.util.Scanner;

public class Palindrome {

    public static void main(String[] arg){

        Scanner sc=new Scanner(System.in);

        System.out.println("Enter a Number");

        int i=sc.nextInt();

        int j=i;

        int a,rev=0;

        while(i>0){

           a=i%10; 

           rev=rev*10+a;

           i=i/10;

        }

        System.out.println("reverse number is :"+rev); 

        if(j==rev){

            System.out.println("given number is palindrome"); 

        }

        else{

             System.out.println("given number is not palindrome");

        }        

    }    

}

/*

Output1:

Enter a Number

123

reverse number is :321

given number is not palindrome

Output2:

Enter a Number

121

reverse number is :121

given number is palindrome

*/

Print numbers in triangle format

Print numbers in triangle format

public class TriangleTest {

    public static void main(String[] arg){

        int a=1;

        for(int i=1;i<=4;i++){

            for(int space=i;space<4;space++){

            System.out.print(" ");   // for print spaces

            }

            for(int j=1;j<=i;j++){

                System.out.print(a+" ");//print number

                a++;

            }

            System.out.println();// for new line

        }

    }

/*

Output:

   1

  2 3

 4 5 6

7 8 9 10

*/

Print digit sum program in java

Print digit sum program in java

Here in this program if we enter any number, calculate and print sum

For example: number is 123

1+2+3=6, sum is 6

import java.util.Scanner;

public class DigitSum {

   public static void main(String[] arg){

        Scanner sc=new Scanner(System.in);

        System.out.println("Enter a digit : ");

        int num=sc.nextInt();

        int sum=0,a;

        System.out.print(num +" sum is ");

        while(num > 0 )  { 

          a = num % 10;

          sum = sum + a ;

          num = num / 10 ;         

      }

        System.out.println(sum);

    } 

}

/*

Output:

Enter a digit : 

1234

1234 sum is 10

*/

Print sum of digits from 1 to n program in java

Print sum of digits from 1 to n program in java

The main aim of this program is print sum of digits, for example if we want calculate sum of digit 5 we can calculate like this way 1+2+3+4+5=15

Sum of 10 digit=1+2+3+4+5+6+7+8+9+10=65

import java.util.Scanner;

public class SumOfDigit {

    public static void main(String[] arg){

        Scanner sc=new Scanner(System.in);

        System.out.println("Enter a digit :");

        int num=sc.nextInt();

        int sum=0;

        for(int i=1;i<=num;i++){

            sum+=i;//(or) sum=sum+i;

        }

        System.out.println("sum of digits from 1 to "+num +" : "+sum);

    }

}

Print Square in java

Print Square in java

public class PrintSquare {

    public static void main(String[] arg){

                               //print first line

        for(int i=1;i<=15;i++){

            System.out.print("*");

        }                    

        System.out.println("");//print new line

                               //print first *

        for(int j=1;j<=5;j++){

            System.out.print("*");

                                              //print spaces

            for(int space=1;space<=13;space++){

                System.out.print(" ");

            }                                

            System.out.print("*");//print end *

            System.out.println("");//print new line

        }

         for(int i=1;i<=15;i++){

            System.out.print("*");//print end line

        }       

    }   

}

/*

Output:

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

*                   *

*                   *

*                   *

*                   *

*                   *

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

*/

Print prime numbers in java

Print prime numbers

Prime numbers can divisible by 1 and itself only.

import java.util.Scanner;

public class PrimeNumbers {

    public static void main(String[] arg){

        int number;

        Scanner sc=new Scanner(System.in);

        System.out.println("Enter number :");

        number=sc.nextInt();              

        System.out.println("Prime numbers from 1 to " + number);

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

              boolean isPrime = true;

              //to check it is prime or not

              for(int j=2;j<i;j++){

                    if(i%j==0){

                       isPrime = false;

                       break;

                      }

                 }                       

                       if(isPrime)

                          System.out.print(i + " ");

           }       

    }

}

/*

Output:

Enter number :

20

Prime numbers from 1 to 20

1 2 3 5 7 11 13 17 19

*/

Print odd numbers in java

Print odd numbers in java

Any integer number is divisible by 2 and produces remainder is a fraction then that integer number is odd number.

import java.util.Scanner;

public class OddNumbers {

   public static void main(String[] arg){

        int number;

        Scanner sc=new Scanner(System.in);

        System.out.println("Enter any number :");

        number=sc.nextInt();

        System.out.println("Odd Numbers are");

        for(int i=0;i<=number;i++){

          if(i%2!=0){

              System.out.print(i+" ");

          }  

        }        

    } 

}

/*

Output:

Enter any number :

20

Odd Numbers are

1 3 5 7 9 11 13 15 17 19

*/

Print even numbers in java

Print even numbers in java

Any integer number is divisible by 2 and produces zero remainder, that integer number is even number.

import java.util.Scanner;

public class EvenNumbers {

    public static void main(String[] arg){

        int number;

        Scanner sc=new Scanner(System.in);

        System.out.println("Enter any number :");

        number=sc.nextInt();

        System.out.println("Even Numbers are");

        for(int i=0;i<=number;i++){

          if(i%2==0){

              System.out.print(i+" ");

          } 

        }       

    }   

}

/*

Output:

Enter any number :

20

Even Numbers are

0 2 4 6 8 10 12 14 16 18 20

*/

if condition program in java

if condition program in java

If condition in java:

“if “ is a conditional statement is java, it is check the condition only once. If condition is true then conditional block will be execute. If condition is false then “if” block will be exit and execute the else block.

Syntax:

if(condition){

               .........

               statments ........

}

               else{

                       ...........

                     statmetns ........

               }

 public class IfCondTest {

    public static void main(String args[])  {

        int a=30,b=20;

        if(a>b)  {

           System.out.println("a is greater");

        }

        else{

            System.out.println("b is greater"); 

        }

    }    

}

Output:

a is greater

Example for else if condition:

public class IfCondTest {

    public static void main(String args[])  {

        int a=10,b=20;

        if(a>b) {

           System.out.println("a is greater");

        }

        else if(b>a)  {

            System.out.println("b is greater"); 

        }

        else{

           System.out.println("a and b are equal");  

        }

    }    

}

Output:

b is greater

Nested If condition (if condition inside if condition block):

public class IfCondition {

    public static void main(String args[])  {

        int a=10,b=20;

        if(a<b) {

           System.out.println("a is lessthen b");

            if(b>a) {

            System.out.println("b is greater"); 

        }

        }        

        else{

           System.out.println("a and b are equal");  

        }

    }    

}

Output:

a is lessthen b

b is greater

Multiple conditions inside if: 

if(a<b&&b>c) in this case both conditions should be true,

if(a<b||b>c) in this case at least one condition should be true,

public class IfCondition {

    public static void main(String args[])   {

        int a=10,b=20,c=30;

        if(a<b&&b>c)  {

           System.out.println("a is lessthen b");            

        }       

        else{

           System.out.println("a greaterthen b");  

        }

    }    

}

Output:

a greaterthen b