program to check prime number in java

[Bansi_WADIA]

Hi,
I get this program "to check entered number is prime number or not" in my exam.I tried various method but I am not able to write this program.So I am just asking solution of this program on this forum.If any one have solution of this program please give it to me.
Thanks in advanced.

[kelfro]

I write this program just using if statement.Try to compile this program in your computer.

 class PrimeNumber
        {
         public static void main(String[] args) 
                {
                int Num1 = 11;
                int p;
                for (p=2; pi < Num ;p++ )
                    {
                     int x = num%p;
                     if (x==0)
                       {
                        System.out.println("Entered number is not Prime!");
                         break;
                        }
                     }
                if(p == Num)
                {
                  System.out.println("Prime number!");
          }
  }
}

[Zecho]

Try following code to check prime number.

           class PrimeNumber
              {

                public static void main(String args[])
                       {

                      int Num = Integer.parseInt(args[0]);

                      int opt=0;

                     for(int p=2;p<num;p++)
                       {

                       if(num%p==0)

                         {

                         System.out.println(Num+" is not a Prime Number");

                         opt = 1;

                         break;

                         }

                      }

                      if(opt==0)

                     System.out.println(Num+" is a Prime Number");

    }

}

[Reegan]

I just write program which is small but very complex.Try to understand each step.

        public static boolean prime (long PrimeNmber)
	{
	    for (int x=1; x<PrimeNmber; x+=2)
		{
		if ((PrimeNmber%x==0 && x!=1) || (PrimeNmber%2==0 && PrimeNmber!=2))
			{	
			return false;
			}
		}
		return true;
	}

I think this will help you.