Write a Program in Java to print all the Twin Prime numbers within a given range
Answers
Answer:
Note: Twin Prime numbers are a pair of numbers which are both prime and their difference is 2.
Example: Twin Prime numbers in the range 1 to 100 are :
(3,5) (5,7) (11,13) (17,19) (29,31) (41,43) (59,61) (71,73)
Programming Code:
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/**
* The class TwinPrimeRange inputs 2 numbers and prints all the
* twin prime numbers within that range
* @author : www.guideforschool.com
* @Program Type : BlueJ Program - Java
*/
import java.util.*;
class TwinPrimeRange
{
boolean isPrime(int n) //funton for checking prime
{
int count=0;
for(int i=1; i<=n; i++)
{
if(n%i == 0)
count++;
}
if(count == 2)
return true;
else
return false;
}
public static void main(String args[])
{
TwinPrimeRange ob = new TwinPrimeRange();
Scanner sc = new Scanner(System.in);
System.out.print("Enter the lower range : ");
int p = sc.nextInt();
System.out.print("Enter the upper range : ");
int q = sc.nextInt();
if(p>q)
System.out.println("Invalid Range !");
else
{
System.out.println("\nThe Twin Prime Numbers are : ");
for(int i=p; i<=(q-2); i++)
{
if(ob.isPrime(i) == true && ob.isPrime(i+2) == true)
{
System.out.print("("+i+","+(i+2)+") ");
}
}
}
}
}
Output:
Enter the lower range : 1
Enter the upper range : 200
The Twin Prime Numbers within the given range are :
(3,5) (5,7) (11,13) (17,19) (29,31) (41,43) (59,61) (71,73) (101,103) (107,109) (137,139) (149,151) (179,181) (191,193) (197,199)
Explanation:
hope this helps