Golang 數組模拟環形隊列

package main

import (
	"errors"
	"fmt"
	"os"
)

type CircleQueue struct {
	head    int
	tail    int
	array   [5]int
	maxSize int
}

func (this *CircleQueue) IsFull() bool {
	return (this.tail+1)%this.maxSize == this.head
}
func (this *CircleQueue) IsEmpty() bool {
	return this.tail == this.head
}
func (this *CircleQueue) Size() int {
	return (this.tail + this.maxSize - this.head) % this.maxSize
}

func (this *CircleQueue) Push(val int) (err error) {
	if this.IsFull() {
		return errors.New("Queue Full")
	}
	this.array[this.tail] = val
	this.tail = (this.tail + 1) % this.maxSize
	return
}

func (this *CircleQueue) Pop() (v int, err error) {
	if this.IsEmpty() {
		return -2, errors.New("Queue is Empty.")
	}
	v = this.array[this.head]
	this.head = this.head + 1
	return
}

func (this *CircleQueue) List() {
	fmt.Println("Circle Queue as tHIS queue.")
	size := this.Size()
	if size == 0 {
		fmt.Println("Your Queue Is  Empty.")
	}
	temp := this.head
	for i := 0; i < size; i++ {
		fmt.Printf("array[%d]=%d", temp, this.array[temp])
		temp = (temp + 1) % this.maxSize
	}
}

func main() {
	// 1,2,3,4,0
	// 滿:
	// 	(tail + 1) % maxsize == head
	// 空:
	// 	tail == head
	// 有多少個:
	// 	(tail + maxsize -head) % maxsize

	array := &CircleQueue{
		head:    0,
		tail:    0,
		maxSize: 5,
	}
	var (
		key   string
		value int
		err   error
	)
	for {
		fmt.Println("push: for push value into array")
		fmt.Println("pop: for pop value into array")
		fmt.Println("list: for show value into array")
		fmt.Println("exit:")
		fmt.Println("Please Give me Your KeyWord.")
		fmt.Scanln(&key)

		switch key {
		case "push":
			fmt.Println("Please give me you value.")
			fmt.Scanln(&value)
			if err = array.Push(value); err != nil {
				fmt.Println(err)
			} else {
				fmt.Println("Add this array Successed.")
			}
		case "list":
			array.List()
		case "pop":
			if val, err := array.Pop(); err != nil {
				fmt.Println(err)
			} else {
				fmt.Println("\nvalue:", val)
			}
		case "exit":
			os.Exit(0)
		case "bianli":
			fmt.Println(array.array)
		}
	}
}