Java program to print prime numbers from 2 to N

Let’s learn how do you print prime numbers from 2 to N in java program?

Java program to print prime numbers from 2 to N

Prime number is one which is divisible by 1 and itself. In the below java program let’s find prime numbers from 2 to N.

First we read input from user or maximum number using nextInt() method of Scanner class and loop from 2 to N using findPrime() method.

In this findPrime() method we will find whether number is prime or not. In this for loop if condition divides any number between 2 to (number/2)-1 then number will not be prime number. Here’s program to print prime numbers from 2 to N.

import java.util.Scanner;
public class PrimeNumberFrom2Ton
{
   public static void main(String[] args) 
   {
      int loop, max;
      System.out.print("Please enter highest (maximum) number: ");
      Scanner sc = new Scanner(System.in);
      max = sc.nextInt();
      for(loop = 2; loop < max; ++loop)
      {
         if(findPrime(loop))
         {
            System.out.println(loop);
         }
      }
      sc.close();
   }
   public static boolean findPrime(int number)
   {
      int a;
      boolean boolPrime = true;
      for(a = 2; a < number / 2; a++)
      {
         if(number%a == 0)
         {
            boolPrime = false;
            break;
         }
      }
      return boolPrime;
   }
}

Output:

Please enter highest (maximum) number: 20
2
3
4
5
7
11
13
17
19

Please enter highest (maximum) number: 30
2
3
4
5
7
11
13
17
19
23
29