Error: redeclaration

Question

I keep on getting the error: invalid redeclaration of 'decreaseLife(by):'. I don't understand why, since it was originally declared within a protocol. 
Here is my code:
enum Direction {
    case up, down, left, right
}
protocol Movable {
    func move(_ direction: Direction, by distance: Int)
}
protocol Destructable {
    func decreaseLife(by factor: Int)
}
protocol Player: Destructable {
    var position: Point { get set }
    var life: Int { get set }
    init(x:Int, y: Int)
}
protocol Attacker {
    var strength: Int { get }
    var range: Int { get }
func attack(player: Player)
}
struct Point {
    let x: Int
    let y: Int
init(x: Int, y: Int) {
    self.x = x
    self.y = y
}

/// Returns the 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
}
}
// Enemy
class Enemy: Player, Attacker {
    var life: Int = 2
    var position: Point
    var strength: Int = 5
    var range: Int = 2
required init(x: Int, y: Int) {
    self.position = Point(x: x, y: y)
}

func decreaseLife(by factor: Int) {
    life -= factor
}

//MARK: - Destructable
func decreaseLife(by factor: Int) {
    life -= factor
}

func attack(player: Player) {
    player.decreaseLife(by: strength)
}

func move(_ direction: Direction, by distance: Int) {
    switch direction {
        case .up: position = Point(x: position.x, y: position.y + 1)
        case .down: position = Point(x: position.x, y: position.y - 1)
        case .right: position = Point(x: position.x + 1, y: position.y)
        case .left: position = Point(x: position.x - 1, y: position.y)

}
}
}
// Tower
class Tower {
    let position: Point
    var range: Int = 1
    var strength: Int = 1
init(x: Int, y: Int) {
    self.position = Point(x: x, y: y)
}

func fire(at enemy: Enemy) {
    if isInRange(of: enemy) {
        enemy.decreaseLife(by: strength)
        print("Gotcha")
    } else {
        print("Darn! Out of range!")
    }
}

func isInRange(of enemy: Enemy) -> Bool {
    let availablePositions = position.points(inRange: range)

for point in availablePositions {
        if point.x == enemy.position.x && point.y == enemy.position.y {
            return true
        }
    }

return false
}
}

Chris Stromberg · Answer

You have declared this method twice with the same signature:
```swift
func decreaseLife(by factor: Int) {
    life -= factor
}
//MARK: - Destructable
func decreaseLife(by factor: Int) {
    life -= factor
}
```
You can't do that. Delete one, change the func name, or change the parameter name to fix the problem.

Welcome to the Treehouse Community

Looking to learn something new?

Charlotte Dorn

Charlotte Dorn

Error: redeclaration

1 Answer

Chris Stromberg

Chris Stromberg

Otto linden

Otto linden