swift使用数组实现队列的push和pop

//定义的异常处理类型
enum QueueError: Error {
    case QueueIsEmpty
    case QueueIsFull
}

class Queue: NSObject {
    
    var array:Array<Int> //存储数据
    var font:Int //队列头部
    var rear:Int //队列尾部
    var size:Int //队列长度
    
    //重载构造函数init，传入需要创建的队列大小
    init(_ size: Int) {
        self.array = Array(repeating:0, count: size)
        self.font = 0
        self.rear = -1
        self.size = 0
        super.init()
    }
    //添加数据到队列中
    public func push(_ addData: Int) throws {
        if self.size >= self.array.count {
            throw QueueError.QueueIsFull
        }
        
        if self.rear == self.array.count - 1 {
            self.rear = -1
        }
        
        self.rear += 1
        self.array[self.rear] = addData
        self.size += 1
    }
    //删除数据到队列中
    public func pop() throws -> Int {
        if self.size == 0 {
            throw QueueError.QueueIsEmpty
        }
        let data = self.array[self.font]
        self.font += 1
        if self.font == self.array.count {
            self.font = 0
        }
        self.size -= 1
        return data
    }
    //队列是否为空
    public func isEmpty() -> Bool {
        return self.size == 0
    }
    //队列是否已满
    public func isFull() -> Bool {
        return self.size == self.array.count
    }
}

方法调用

        //初始化，5个长度的队列
        let queue1 = Queue(5)
        do {
            //向队列中添加数据
            try queue1.push(10)
            try queue1.push(20)
            try queue1.push(30)
            try queue1.push(40)
            try queue1.push(50)
            //队列长度为5，会导致异常，
            try queue1.push(60)
        } catch QueueError.QueueIsFull {
            print("队列已满")
        } catch {
            
        }
        
        print("queue is empty:\(queue1.isEmpty())")
        print("queue is full:\(queue1.isFull())")
        
        do {
            //取出队列中的数据
            try print(queue1.pop())
            try print(queue1.pop())
            try print(queue1.pop())
            try print(queue1.pop())
            try print(queue1.pop())
            try print(queue1.pop())
            
        } catch QueueError.QueueIsEmpty{
            print("队列为空")
        } catch {
            
        }
        print("queue is empty:\(queue1.isEmpty())")
        print("queue is full:\(queue1.isFull())")

执行结果：

队列已满  //这行输出是执行 try queue1.push(60)触发的异常
queue is empty:false
queue is full:true
10
20
30
40
50
队列为空
queue is empty:true
queue is full:false