便利初始化器不断崩溃，但指定初始化器工作正常？

Question

当使用便利初始化器创建实例时，playground 一直给我这个错误 "error: Execution was interrupted, reason: EXC_BAD_ACCESS (code=2, address=0x7ffee5ae9ff8)" 但是当使用指定初始化器时它工作正常。

我不完全确定我是否正确设置了便利初始化程序，以便在创建新实例时只需要 arsenal 参数。

class FootballTeams {

 var liverpool: String
 var chelsea: String
 var manchesterunited: String
 var arsenal: String = "fourth"

 init(arsenal:String, chelsea:String,     
      liverpool: String, manchesterunited:String ) { //designated initialiser
    self.arsenal = arsenal
    self.chelsea = chelsea
    self.liverpool = liverpool
    self.manchesterunited = manchesterunited
}

 convenience init(arsenal: String){
    self.init(arsenal: arsenal) //call to designated initialiser   above
    self.arsenal = arsenal
}
}

let properInstance = FootballTeams(arsenal: "Overides stored  property value", chelsea: "a", liverpool: "b", manchesterunited: "b")
print(properInstance.arsenal)

let convenienceInstance = FootballTeams(arsenal: "This is an instance from the convenience init")
print(convenienceInstance.arsenal)

Answer 1

你运行进入了一个无限循环，你没看到警告吗

All paths through this function will call itself

这意味着 init(arsenal 调用 init(arsenal 调用 init(arsenal 调用 init(arsenal 调用 init(arsenal ......

要调用便捷初始化程序，您必须调用指定的初始化程序并提供默认值

convenience init(arsenal: String) {
    self.init(arsenal: arsenal, chelsea:"sixth", liverpool: "first", manchesterunited: "fifth") //call to designated initialiser   above
}

额外的行 self.arsenal = arsenal 是多余的。

便利初始化器不断崩溃，但指定初始化器工作正常？

Convenience initialiser keeps crashing however designated initialiser works fine?

swift

initialization

init

swift-playground

convenience-methods