package queue

import (

    "errors"

    "fmt"

)

//CircleQueue 环型队列

type CircleQueue struct {

    MaxSize int

    Array   []int

    Front   int

    Rear    int

}

//Push 向队列中添加一个值

func (q *CircleQueue) Push(val int) (err error) {

    //先判断队列是否已满

    if q.IsFull() {

        return errors.New("队列已满")

    }

    q.Array[q.Rear] = val

    //队尾不包含元素

    //q.Rear++

    q.Rear = (q.Rear + 1) % q.MaxSize

    return

}

//Pop 得到一个值

func (q *CircleQueue) Pop() (val int, err error) {

    if q.IsEmpty() {

        return -, errors.New("队列已空")

    }

    //队首包含元素

    val = q.Array[q.Front]

    //q.Front++

    q.Front = (q.Front + 1) % q.MaxSize

    return val, err

}

//IsFull 队列是否满了

func (q *CircleQueue) IsFull() bool {

    return (q.Rear+1)%q.MaxSize == q.Front

}

//IsEmpty 队列是否为空

func (q *CircleQueue) IsEmpty() bool {

    return q.Front == q.Rear

}

//Size 队列的大小

func (q *CircleQueue) Size() int {

    return (q.Rear + q.MaxSize - q.Front) % q.MaxSize

}

//Show 显示队列

func (q *CircleQueue) Show() {

    //取出当前队列有多少元素

    size := q.Size()

    if size ==  {

        fmt.Println("队列为空")

    }

    //辅助变量，指向Front

    tmpFront := q.Front

    for i := ; i < size; i++ {

        fmt.Printf("queue[%d]=%v\t", tmpFront, q.Array[tmpFront])

        tmpFront = (tmpFront + 1) % q.MaxSize

    }

}

package main

import (

    "fmt"

    "go_code/data_structure/queue"

    "os"

)

func main() {

    var key string

    var val int

    q := &queue.CircleQueue{

        MaxSize: ,

        Front:   ,

        Rear:    ,

    }

    for {

        fmt.Println("------------------------------")

        fmt.Println("1.输入push表示添加数据到队列")

        fmt.Println("2.输入pop表示从队列中获取数据")

        fmt.Println("3.输入show表示显示队列")

        fmt.Println("4.输入exit表示退出")

        fmt.Println("------------------------------")

        fmt.Scanln(&key)

        switch key {

        case "push":

            fmt.Println("请输入要添加的值：")

            fmt.Scanln(&val)

            err := q.Push(val)

            if err != nil {

                fmt.Println(err)

            } else {

                fmt.Println("添加成功")

                fmt.Println("Rear：", q.Rear)

            }

        case "pop":

            val, err := q.Pop()

            if err != nil {

                fmt.Println(err)

            } else {

                fmt.Println("得到的值为：", val)

                fmt.Println("Front：", q.Front)

            }

        case "show":

            q.Show()

            fmt.Println()

        case "exit":

            os.Exit()

        }

    }

}