How to find sum of first N numbers in swift ?

# Question 1: Find sum of first n numbers. Example :– n = 3 => 3+2+1 =6. We will use recursion to solve this problem.

func sumOfNNumber(number: Int, sum: inout Int) -> Int{
    if number < 1 {
        return sum
    }
    sum += number
    sumOfNNumber(number: number - 1, sum: &sum)
    return sum
}
var sumValue = 0
sumOfNNumber(number: 3, sum: &sumValue)
print(sumValue)

// Approach 2 sun of first n mumbers

func sumOfFirstNNumer(number: Int) -> Int {
    if number == 0 { return 0 }
    return number + sumOfFirstNNumer(number: number - 1)
}
print(sumOfFirstNNumer(number: 4))

# Question 2: Find sum of array elements using recursion approach :

func sumOfArray(inArray: [Int], arrayCount: inout Int, sum: inout Int)  {
    if arrayCount <= 0 {
        return
    }
    arrayCount -= 1
    sum += inArray[arrayCount]
    sumOfArray(inArray: inArray, arrayCount: &arrayCount, sum: &sum)
}


var arrayInput = [1,2,3,4,5,6]
var arrayCount = arrayInput.count
var sum = 0
sumOfArray(inArray: arrayInput, arrayCount: &arrayCount, sum: &sum)
print(sum)