generatePrimeNumbersRange()

Step 1: Understanding the Problem

In order to generate prime numbers in a given range, we first need to understand what a prime number is. A prime number is a number that has no positive divisors other than 1 and itself. For example, the first six prime numbers are 2, 3, 5, 7, 11, and 13. To generate a list of prime numbers in a range, we need to iterate over each number in the range and check whether it is prime or not.

for num in lowerBound...upperBound {
    // We will implement the prime check here
}

Step 2: Checking for prime numbers

In this step, we will write a helper function isPrime(_:) to check if a number is prime or not. If the number is less than 2 or not an integer then it's not a prime number. If it's 2 then it is a prime number. Otherwise, we should check if it has any divisors up to its square root.

func isPrime(_ number: Int) -> Bool {
    if number < 2 { return false }
    if number == 2 { return true }
    for i in 2...Int(sqrt(Double(number))) {
        if number % i == 0 {
            return false
        }
    }
    return true
}

Step 3: Generating prime numbers

After defining our helper function to check prime numbers, we will use it to filter the numbers in the given range which are prime.

func generatePrimes(lowerBound: Int, upperBound: Int) -> [Int] {
    let numbers = Array(lowerBound...upperBound)
    let primes = numbers.filter({isPrime($0)})
    return primes
}

Step 4: Testing the function

To ensure our function is working correctly, we should test it with different ranges of numbers.

generatePrimes(lowerBound: 10, upperBound: 50) // it should return [11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47]

Conclusion

By compartmentalizing the task into smaller problems i.e., checking if a number is prime and then filtering prime numbers in a range, we successfully implemented the function generatePrimes(lowerBound:upperBound:) that generates all prime numbers in a given range. Swift's inbuilt filter function greatly simplified our task.