Java Program to Check Whether a Number can be Expressed as Sum of Two Prime Numbers

# Java Program to Check Whether a Number can be Expressed as Sum of Two Prime Numbers

#### 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

``````public class CheckPrime {

public static void main(String[] args) {
int number = 34;
boolean flag = false;
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)) {

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:

```34 = 3 + 31
34 = 5 + 29
34 = 11 + 23
34 = 17 + 17```