In this program, you'll learn to check whether a given number can be expressed as a sum of two prime numbers or not. This is done with the help of loops and break statements in Java.
To accomplish this task, checkPrime() function is created.
The checkPrime() returns 1 if the number passed to the function is a prime number.
Example: Integer as a Sum of Two Prime Numbers
Programming code:
import java.util.*;
public class CheckPrime
{
public static void main(String[] args)
{
int number;
boolean flag = false;
Scanner sc=new Scanner(System.in);
System.out.println("Enter any number:");
number=sc.nextInt();
for (int i = 2; i <= number / 2; ++i)
{
// condition for i to be a prime number
if (checkPrime(i))
{
// condition for n-i to be a prime number
if (checkPrime(number - i))
{
// n = primeNumber1 + primeNumber2
System.out.printf("%d = %d + %d\n", number, i, number - i);
flag = true;
}
}
}
if (!flag)
System.out.println(number + " cannot be expressed as the sum of two prime numbers.");
}
// Function to check prime number
static boolean checkPrime(int num)
{
boolean isPrime = true;
for (int i = 2; i <= num / 2; ++i)
{
if (num % i == 0)
{
isPrime = false;
break;
}
}
return isPrime;
}
}
When you run the program, the output will be:
Enter any number:
48
48 = 5 + 43
48 = 7 + 41
48 = 11 + 37
48 = 17 + 31
48 = 19 + 29
