队列——循环队列与非循环队列（java版）-凯发app官方网站

import java.awt.font;

import java.util.scanner;

import javax.management.runtimeerrorexception;

public class circlearrayqueuedemo {

public static void main(string[] args) {

//创建队列

circlearrayqueue circlearrayqueue = new circlearrayqueue(4);

char key = ' ';

scanner scanner = new scanner(system.in);

boolean loop = true;

while(loop) {

system.out.println("s(show):显示队列");

system.out.println("e(exit):退出程序");

system.out.println("a(add):添加数据到队列");

system.out.println("g(get):从队列取出数据");

system.out.println("h(head):查看队列头的数据");

key = scanner.next().charat(0);

switch (key) {

case 's':

circlearrayqueue.showqueue();

break;

case 'e':

circlearrayqueue.showqueue();

break;

case 'a':

system.out.println("输入一个数");

int value = scanner.nextint();

circlearrayqueue.addqueue(value);

break;

case 'g':

try {

int res = circlearrayqueue.getqueue();

system.out.printf("取出的数据是%d\n",res);

}catch (exception e) {

system.out.println(e.getmessage());

}

break;

case 'h':

try {

int res = circlearrayqueue.headqueue();

system.out.printf("队列头的数据是%d\n",res);

}catch (exception e) {

system.out.println(e.getmessage());

}

break;

default:

scanner.close();

loop = false;

break;

}

}

system.out.println("程序退出");

}

}

//队列

class circlearrayqueue{

private int maxsize;

private int front;

private int rear;

private int[] arr;

//构造器

public circlearrayqueue(int arrmaxsize) {

maxsize = arrmaxsize;

front = 0;

rear = 0;

arr = new int[maxsize];

}

//判满

public boolean isfull() {

return (rear 1)%maxsize == front;

}

//判空

public boolean isempty() {

return rear == front;

}

//入队

public void addqueue(int n) {

if(isfull()) {

system.out.println("队列已满，不能再添加！");

return;

}

//添加数据

arr[rear] = n;

//rear后移

rear = (rear 1) % maxsize;

}

//出队

public int getqueue() {

if(isempty()) {

throw new runtimeexception("队列为空，不可取出元素！");

}

//取值

int value = arr[front];

//front后移

front = (front 1)%maxsize;

return value;

}

//遍历

public void showqueue() {

if(isempty()) {

system.out.println("队列为空!");

return;

}

for(int i = front; i < front  size(); i ) {

system.out.printf("arr[%d]=%d\n",i % maxsize, arr[i % maxsize]);

}

}

//求队列有效数据的个数

public int size() {

return (rear maxsize - front) % maxsize;

}

//显示队头元素

public int headqueue() {

if(isempty()) {

throw new runtimeexception("队列为空，不可取出元素！");

}

return arr[front];

}

}