prime number program in java using user input code example

Example 1: Prime number program in java using scanner

// Prime number program in java using scanner
import java.util.Scanner;
public class PrimeNumberUsingScanner 
{
   public static void main(String[] args) 
   {
      Scanner sc = new Scanner(System.in);  
      System.out.println("Please enter a number to check prime number: ");  
      int number = sc.nextInt();  
      if(checkPrimeNumber(number)) 
      {  
         System.out.println(number + " is a prime number");  
      }
      else 
      {  
         System.out.println(number + " is not a prime number");  
      }
      sc.close();
   }
   public static boolean checkPrimeNumber(int number) 
   {  
      if(number <= 1) 
      {  
         return false;
      }  
      for(int a = 2; a < Math.sqrt(number); a++) 
      {  
         if(number % a == 0) 
         {  
            return false;  
         }  
      }  
      return true;  
   }
}

Example 2: prime number program in java

public class Prime {
    public static void main(String[] args) {

        int num = 29;
        boolean flag = false;
        for(int i = 2; i <= num/2; ++i){
            if(num % i == 0){
                flag = true;
                break;
            }
        }

        if (!flag)
            System.out.println(num + " is a prime number.");
        else
            System.out.println(num + " is not a prime number.");
}}