sum of prime numbers in java code example

Example 1: java prime numbers

public class Main {
  public static void main(String[] args) {
    for (int i = 2; i < 1_000_000; ++i) {
      boolean isPrime = true;
      int sqrt = (int)Math.ceil(Math.sqrt(i));
      for (int divisor = 2; divisor <= sqrt; ++divisor) {
        if (i % divisor == 0) {
          isPrime = false;
          break;
        }
      }
      if (isPrime) {
        System.out.println(i);
      }
    }
  }
}

Example 2: sum of prime numbers in a digit in java

import java.util.*;
public class PrimeDigit
{
    public boolean IsPrime(int i)
    {
        boolean b=true;
        int d=2;
        while(d<i/2)
        {
            if (i%d==0)
            {
                b=false;
                break;
            }
            d++;
        }
        return b;
    }
    public static void main(String []args)
    {
       Scanner sc=new Scanner(System.in);
       System.out.print("Enter A Number : ");
       int i=sc.nextInt();
       int s=0,r;
       PrimeDigit pd=new PrimeDigit();
       while(i>0)
       {
            r=i%10;
            if(pd.IsPrime(r))
			{
                s = s + r;
			}
            i = i / 10;
       }
       System.out.print("Sum Of The Prime Digits : " + s );
    }
}

Example 3: sum of numbers in java

public class SumNatural {

    public static void main(String[] args) {

        int num = 100, sum = 0;

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

        System.out.println("Sum = " + sum);
    }
}