Kotlin 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 Kotlin.

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

fun main(args: Array<String>) {
    val number = 34
    var flag = false
    for (i in 2..number / 2) {

        // 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)
        println("$number cannot be expressed as the sum of two prime numbers.")
}

// Function to check prime number
fun checkPrime(num: Int): Boolean {
    var isPrime = true

    for (i in 2..num / 2) {
        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

Here's the equivalent Java code: Java Program to Repesent a Number as a sum of two numbers.