PROGRAM
Christian Goldback has conjectured for N<1014
that every even N>2, can be represented as sum of two primes. For example,
18=5+13.
WAP that reads N which should be
an even number>2 and represents it as sum of two primes.
/**
* class ChristianGoldback find two prime numbers whose sum is equal to a given number.
* @author: Nitendra Verma
* @version: June 10,2013
*/
import java.util.Scanner;
public class ChristianGoldback
{
int n,count=0; //instance variables
public void getnum(int nn) //method to assign parameter to number
{
n=nn;
}
public void check() //method to find prime numbers whose sum is equal to given number
{
int g1[]=new int[n];
int flag=0;
for(int i=3;i<n;i++) //outer loop
{
flag=1;
for(int j=2;j<i;j++) //inner loop
{
if(i%j==0)
{
flag=0;
break;
}
}
if(flag==1)
{
g1[count]=i;
count++;
}
}
System.out.println("Number can be represented as sum of two primes:");
for(int i=0;i<count/2;i++)
{
for(int j=0;j<count;j++)
{
if((g1[i]+g1[j])==n)
{
System.out.println(n +"=" +g1[i]+"+" +g1[j]);
}
}
}
}
public static void main()
{
ChristianGoldback ob=new ChristianGoldback(); //creating object of class ChristianGoldback
Scanner in=new Scanner(System.in); ////creating object of class Scanner
System.out.println("Enetr a num");
int num=in.nextInt();
ob.getnum(num); //calling method
ob.check(); //calling method
}
}
OUTPUT
Enetr a num
18
Number can be represented as sum of two primes:
18=5+13
18=7+11
/*---------------Program developed by: Nitendra Verma---------------*/
