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Start your free trial###### Djon Ts

**iOS Development**Techdegree Student 337 Points

# OOP

Hello,

I have watched the lesson, though I do not understand this part:

struct Point { let x: Int let y: Int

```
init(x: Int, y: Int) {
self.x = x
self.y = y
}
/// Returns surrounding points in range of
/// the current one
func points(inRange range: Int = 1) ->[Point] {
var results = [Point]()
let lowerBoundOfXRange = x - range
let upperBoundOfXRange = x + range
let lowerBoundOfYRange = y - range
let upperBoundOfYRange = y + range
for xCoordinate in lowerBoundOfXRange...upperBoundOfXRange {
for yCoordinate in lowerBoundOfYRange...upperBoundOfYRange {
let coordinatePoint = Point(x: xCoordinate, y: yCoordinate)
results.append(coordinatePoint)
}
}
return results
}
```

}

even if I change the value for range to 2 or 3 xCode shows values for (x - range ; x + range) and (y - range ; y + range) to be -1 ; 1 for x and -1 ; 1 for y. I also do not understand why it shows -1 and 1 if we have not provided any values for x and y coordinates yet. Here is the screenshot for better understanding: https://screencast.com/t/MnK20aJ0K

As you can see on the screenshot I entered 2 as a range value however x +- and y+- are the same.

Any help is much appreciated!!!

## 2 Answers

###### Marcus Klausen

17,425 PointsWell I pasted your code into xcode and removed the **= 1** from your **range** parameter.
-Since I define it at instance creation.

and when i do

```
let point = Point(x: 2, y: 2)
point.points(inRange: 2)
```

I get an array of 0,0 up to 4,4 which is correct?

Remember this is an instance method! You have to create an instance **let point = Point(x: 2, y: 2)** and then call the method on the instance **point.methodName()**

second example

```
// create instance and assign to your constant
let yourConstant = Point(x: 2, y: 2)
// call the points() method on your instance which is assigned to yourConstant
yourConstant.points(inRange: 2)
```

Hope this helps :-)

###### Djon Ts

**iOS Development**Techdegree Student 337 Points

Hey Marcus, thank you for the reply. Yep, I understand that it is an instance method. What was unclear for me is: why results showed me coordinates from -1...+1 even when I changed default value for range to 2 or 3 or even delete the default value. This is either a Swift trick or my Xcode is functioning incorrectly and do not show the correct result.

###### Marcus Klausen

17,425 PointsBecause you're initializing the value at the method signature instead of when calling the method.

**points.points(inRange: X)** is where you set the range

not at **func points(inRange range: Int) ->[Point]**

## Djon Ts

iOS DevelopmentTechdegree Student 337 Points## Djon Ts

iOS DevelopmentTechdegree Student 337 PointsHey Marcus, thank you for the reply. Yep, I understand that it is an instance method. What was unclear for me is: why results showed me coordinates from -1...+1 even when I changed default value for range to 2 or 3 or even delete the default value. This is either a Swift trick or my Xcode is functioning incorrectly and do not show the correct result.