findSecondSmallestElement()

Step 1: Define the Function and Handle Edge Cases

We'll start by defining the function findSecondSmallest which will take an array of Integers as an argument. Initially, we will handle the edge cases where the array has less than two elements. In these edge cases the function will just return nil.

func findSecondSmallest(array: [Int]) -> Int? {
    if array.count < 2 {
        return nil
    }
    ...
}

Step 2: Initialize Two Variables

We'll initialize two variables smallest and secondSmallest and set them to maximum integer value, that is, Int.max. We will update these variables as we iterate through the array.

...
    var smallest = Int.max
    var secondSmallest = Int.max
    ...

Step 3: Iteration Through Array

We will iterate through the elements of the array. If we find an element that is less than smallest, then we update secondSmallest with the value of smallest and smallest with the value of the array element. Otherwise, if it's in between smallest and secondSmallest, we just update secondSmallest.

...
    for num in array {
        if num < smallest {
            secondSmallest = smallest
            smallest = num
        } else if num < secondSmallest && num != smallest {
            secondSmallest = num
        }
    }
    ...

Step 4: Handle Case When There is No Second Smallest

After we have iterated through the array, it is possible that secondSmallest has not changed and is still Int.max. In this case, it means that there is no second smallest element in the array and we should return nil.

...
    if secondSmallest == Int.max {
        return nil
    }
    ...

Step 5: Return Second Smallest Element

Finally, if we have passed through all the above conditions, we have our second smallest element of the array. We return secondSmallest.

...
    return secondSmallest
}

In conclusion, we have created a function findSecondSmallest that handles various edge cases and efficiently finds the second smallest value in an array of integers using Swift. The full implementation of the function is:

func findSecondSmallest(array: [Int]) -> Int? {
    if array.count < 2 {
        return nil
    }
    var smallest = Int.max
    var secondSmallest = Int.max
    for num in array {
        if num < smallest {
            secondSmallest = smallest
            smallest = num
        } else if num < secondSmallest && num != smallest {
            secondSmallest = num
        }
    }
    if secondSmallest == Int.max {
        return nil
    }
    return secondSmallest
}