Twisted Prime Number Java

The Twisted Prime number is a special prime number which is also known as the Emirp number. A number is a twisted prime number if the reverse of the number is also a prime number.

Let's take some examples of twisted prime numbers and non-twisted prime numbers.

79 is a twisted prime number because after reversing it, we get 97, i.e., a prime number also.
43 is not a twisted prime number because after reversing it, we get 34, i.e., not a prime number.
37 is also a twisted prime number because after reversing it, we get 73, i.e., a prime number also.

Steps to check twisted prime number

These are the following steps that we can use to implement the logic of twisted prime number:

Take a number from the user to check.
After that, we check whether the number is prime or not because the twisted prime number is a prime number in itself.
If the number is a prime number, we reverse each digit of the number to get a new number.
If the newly generated number is prime, we print "number is a twisted prime number". Otherwise, print "number is not a twisted prime number".

Let's implement the code to check whether the number is a twisted prime number or not.

TwistedPrimeNumbers.java

//import required classes and packages
import java.io.*;
import java.util.*;

//create TwistedPrimeNumbers class to check twisted prime number
class TwistedPrimeNumbers {
 
    // create checkPrimeNumber() method to check whether the number is prime or not
    static boolean checkPrimeNumber(int number)
    {
        int i;
		int m = 0;
		int flag = 0;      
		m = number/2;      
		if(number == 0 || number == 1){  
			return false;      
		}else{  
			for(i = 2; i <= m ;i++){      
				if(number%i == 0){      
					flag=1;      
					return false;     
				}      
			}      
			if(flag == 0)  
			{ 
				return true;
			}  
		}
		return false;
    }
	
	static int getReverseNumber(int number){
		int rev = 0;  
		while(number != 0)   
		{  
			int rem = number % 10;  
			rev = rev * 10 + rem;  
			number = number/10;  
		}
		return rev;
	}
 
    // create checkTwistedPrimeNumber() to check whether the numbers are twisted prime or not
    static boolean checkTwistedPrimeNumber(int number)
    {
        if(checkPrimeNumber(number) && checkPrimeNumber(getReverseNumber(number)))
			return true;
		else
			return false;
    }
 
    /* Driver program to test above function */
    public static void main(String[] args)
    {
         int number1, number2;
		
		//use scanner class for the values of number1 and number2
		Scanner sc = new Scanner(System.in);
		
		//show custom message
		System.out.println("Enter first number");
		
		//store user entered value into variable n1
		number1 = sc.nextInt();
		
		//show custom message
		System.out.println("Enter second number");
		
		//store user entered value into variable n2
		number2 = sc.nextInt();
		
        if (checkTwistedPrimeNumber(number1)) 
            System.out.println(number1 +" is a twisted prime number"); 
        else
            System.out.println(number1 +" is not a twisted prime number"); 
		
		if (checkTwistedPrimeNumber(number2)) 
            System.out.println(number2 +" is a twisted prime number"); 
        else
            System.out.println(number2 +" is not a twisted prime number"); 
        
    }
}

Output:

FindAllTwistedPrimeNumbers.java

//import required classes and packages
import java.util.*;
import java.io.*;

//create FindAllTwistedPrimeNumbers class to get all the twisted prime numbers in the given range
class FindAllTwistedPrimeNumbers {
 
    // create checkPrimeNumber() method to check whether the number is prime or not
    static boolean checkPrimeNumber(int number)
    {
        int i;
		int m = 0;
		int flag = 0;      
		m = number/2;      
		if(number == 0 || number == 1){  
			return false;      
		}else{  
			for(i = 2; i <= m ;i++){      
				if(number%i == 0){      
					flag=1;      
					return false;     
				}      
			}      
			if(flag == 0)  
			{ 
				return true;
			}  
		}
		return false;
    }
	
	static int getReverseNumber(int number){
		int rev = 0;  
		while(number != 0)   
		{  
			int rem = number % 10;  
			rev = rev * 10 + rem;  
			number = number/10;  
		}
		return rev;
	}
 
    // create checkTwistedPrimeNumber() to check whether the numbers are twisted prime or not
    static boolean checkTwistedPrimeNumber(int number)
    {
        if(checkPrimeNumber(number) && checkPrimeNumber(getReverseNumber(number)))
			return true;
		else
			return false;
    }
 
    /* Driver program to test above function */
    public static void main(String[] args)
    {
        int startRange, endRange;
		
		//create scanner class object
		Scanner sc=new Scanner(System.in);
		
		//show custom message
		System.out.println("Enter start value");
		
		//store user entered value into variable startRange
		startRange = sc.nextInt();
		
		//show custom message
		System.out.println("Enter last value");
		
		//store user entered value into variable endRange
		endRange = sc.nextInt();
		
		System.out.println("The twisted prime numbers between" + startRange + " and " + endRange + "are:");
		
		for (int i = startRange; i < endRange; i++) {
            if (checkTwistedPrimeNumber(i)){
                System.out.println(i);
            }
        }
    }
}

Output: