find-square-root()

Step 1: Understanding the Problem

In order to find the square root of a number in Swift, we can use a function from its standard library: sqrt(Double). This function takes a Double as an input and returns its square root. Let's say we want to find the square root of 16. The code would look like this:

import Foundation

let number = 16.0
let squareRoot = sqrt(number)
print(squareRoot)

Step 2: Creating a Function

Now, let's make it into a reusable function. We want our function to accept a Double as an argument, and return a Double:

func findSquareRoot(of number: Double) -> Double {
    return sqrt(number)
}

Step 3: Validating the Argument

Before finding the square root of a number, it's a good idea to validate that it's not negative, because there's no real square root of a negative number. We can handle this case by returning zero or some kind of error. For simplicity, let's just return 0 in this case:

func findSquareRoot(of number: Double) -> Double {
    return number < 0 ? 0 : sqrt(number)
}

Step 4: Testing the Function

Let's call our function with some test values and print the results to verify that it works correctly:

print(findSquareRoot(of: 16.0))   // prints '4.0'
print(findSquareRoot(of: -1.0))   // prints '0.0'
print(findSquareRoot(of: 2.0))    // prints '1.4142135623730951'

Conclusion

To find the square root of a number in Swift, we can use the sqrt(Double) function from the standard library, but it's smart to validate the input before calculating its square root to avoid runtime errors. Here's the final version of our findSquareRoot function:

import Foundation

func findSquareRoot(of number: Double) -> Double {
    return number < 0 ? 0 : sqrt(number)
}

print(findSquareRoot(of: 16.0))  // prints '4.0'
print(findSquareRoot(of: -1.0))  // prints '0.0'
print(findSquareRoot(of: 2.0))   // prints '1.4142135623730951'