I'm just messing around slowly learning Swift, and I decided to make a really simple fighting game. All the below code worked perfectly fine when it was a class, then I decided to change it to a struct, and now on the lines in the function that would reduce the target's hp, it's giving me the following error:
Cannot use mutating member on immutable value
Here is the struct in it's entirety:
struct Player {
let name : String
let maxHealth : Int
var currentHealth : Int
let maxMana: Int
var currentMana: Int
init(playerName: String) {
name = playerName
maxHealth = 100
currentHealth = 100
maxMana = 100
currentMana = 100
}
mutating func swingAt(target: Player) {
if isDead(target: self) {
print("You are dead!")
return
}
let damage = Int.random(in: 0..<10)
target.takeDamage(amount: damage) // Error:Cannot use mutating member on immutable value: 'target' is a 'let' constant
if damage > 0 {
print("\(self.name) does \(damage) damage to \(target.name)!")
}
else {
print("\(self.name) misses \(target.name)!")
}
if isDead(target: target) {
print("\(self.name) has slain \(target.name)!")
}
}
mutating func swingFiveTimesAt(target: Player) {
if isDead(target: self) {
print("You are dead!")
return
}
for _ in 1...5 {
let damage = Int.random(in: 0..<10)
target.takeDamage(amount: damage) // Error:Cannot use mutating member on immutable value: 'target' is a 'let' constant
if damage > 0 {
print("\(self.name) does \(damage) damage to \(target.name)!")
}
else {
print("\(self.name) misses \(target.name)!")
}
}
if isDead(target: target) {
print("\(self.name) has slain \(target.name)!")
}
}
mutating func castFireball(target: Player) {
if isDead(target: self) {
print("You are dead!")
return
}
if self.currentMana < 50 {
print("\(self.name) only has \(self.currentMana), but needs 50 mana to cast this spell!")
return
}
let damage = Int.random(in: 1..<50)
target.takeDamage(amount: damage) // Error:Cannot use mutating member on immutable value: 'target' is a 'let' constant
self.currentMana -= 50
print("\(self.name) throws a huge fireball at \(target.name), doing \(damage) damage!")
if isDead(target: target) {
print("\(self.name) has slain \(target.name)!")
}
}
func isDead(target: Player) -> Bool {
if target.currentHealth <= 0 {
return true
} else {
return false
}
}
mutating func takeDamage(amount: Int) {
self.currentHealth -= amount
}
}
Any ideas how I can achieve the desired functionality?
