find-sum-squares-range()

Step 1

First, let's start off by clearly defining our function. This function, which we'll call findSumOfSquaresInRange, should take two arguments: start and end. These represent the start and the end of the range within which we want to find the sum of squares. In swift, this is how we can define our function:

func findSumOfSquaresInRange(start: Int, end: Int) {
  // we'll fill this in the next steps
}

Step 2

Inside our function, we'll first initialize a variable sum to store our ongoing sum of squares. This should simply be set to 0 initially:

func findSumOfSquaresInRange(start: Int, end: Int) {
  var sum = 0
  // more to come...
}

Step 3

Next, we'll add a for loop that goes from start to end, inclusive. We use the half-open range operator ... to include the end in our range. In each iteration, we'll square the current number and add it to our sum:

func findSumOfSquaresInRange(start: Int, end: Int) {
  var sum = 0
  for number in start...end {
    sum += number * number
  }
  // let's finish this in the next step
}

Step 4

Finally, after calculating the sum of squares, our function should return that value. We can do this by simply adding a return statement at the end of our function. Also, we take care of the case where start is greater than end and return 0:

func findSumOfSquaresInRange(start: Int, end: Int) -> Int {
  if start > end { return 0 }
  var sum = 0
  for number in start...end {
    sum += number * number
  }
  return sum
}

Conclusion

And that's it! With that, our findSumOfSquaresInRange function is complete. This function will return the sum of the squares of all numbers from start to end, inclusive. If start is greater than end, it returns 0.

Here's the final code:

func findSumOfSquaresInRange(start: Int, end: Int) -> Int {
  if start > end { return 0 }
  var sum = 0
  for number in start...end {
    sum += number * number
  }
  return sum
}

This is a basic implementation and assumes that the inputs are valid Integers where start and end are positive numbers. For a more robust solution, you could add checks to ensure valid input.