swift--使用 is 和 as 操作符来实现类型检查和转换

//动物类
class Animal{
    
}
//陆地动物类
class terricole: Animal {
    
}
//海洋动物类
class SeaAnimals: Animal {
    
}

 let cat = terricole()
        let fish = SeaAnimals()
        let arr = [cat,fish]
        
        for anima in arr {
            if anima is terricole{
                print("这是陆地动物")
            }else if anima is SeaAnimals{
                print("这是海洋动物")
            }
        }

for animas in arr {
            if let c = animas as? terricole{
                print("这是陆地动物")
            }else if let w = animas as? SeaAnimals{
                print("这是海洋动物")
            }
        }