Pattern Program

Kaprekar Number

This program checks whether a number is Kaprekar number or not.
A number is said to be Kaprekar number if its sum of digits in its square is the number itself.
Example- 9^2 is 81 and 8+1 is 9.So it is a Kaprekar number.
import java.util.*;
public class KaprekarNumbers
{
    public static void main(String args[])
    {
        Scanner ob=new Scanner(System.in);
        System.out.println("Enter number");
        int n=ob.nextInt();
        int N=n*n;
        int tn=n;int c=0;
        while(tn!=0)
        {
            tn=tn/10;c++;
        }
        int q=(int)(N/Math.pow(10,c));
        int r=(int)(N%Math.pow(10,c));
        if(q+r==n)
            System.out.println("Kaprekar number");
        else
            System.out.println("Non Kaprekar number");

  }

}

Calculating and printing the nth prime number

Calculating and printing the nth prime number

Question:

How to write a java program Given a number n as input, return the value of the nth prime. Note that n is always greater than 0.?

Code:

import java.util.Scanner;
 
public class NthPrime {
 
  public static void main(String[] args) {
 
    Scanner sc = new Scanner(System.in);
 
    System.out.print("Enter n to compute the nth prime number: ");
 
    int nth = sc.nextInt();
 
    int num, count, i;
    num=1;
    count=0;
 
    while (count < nth){
      num=num+1;
      for (i = 2; i <= num; i++){
        if (num % i == 0) {
          break;
        }
      }
      if ( i == num){
        count = count+1;
      }
    }
    System.out.println("Value of nth prime: " + num);
  }
}

Output:

$ java NthPrime
Enter n to compute the nth prime number: 10
Value of nth prime: 29

Pattern program