[Java数据结构]线性表之队列Queue

》》原理

就像排队，先来的先走，后来的等在后面。

》》思路

定义一个数组存放，头指针front指向表头，每次移走一个元素front+1，rear指向头尾，每次增加一个元素rear+1。注意移走和插入的指针指向的区别。

》》代码

package 栈和队列;class queueArr {private int maxSize;private long[] queArr;private int front;// 队头private int rear;// 队尾private int n;public queueArr(int s) {maxSize = s;queArr = new long[maxSize];front = 0;rear = -1;n = 0;}public void insert(int i) {if (!isFull()) {//if (rear == maxSize - 1) {//如果不加这个判断，就会出现数组越界报错了//rear = -1;// 如果加上这句，队尾绕回低端，后加的数会从头排进去//}// 如果是低端，rear+1=0，又是数组queArr[++rear] = i;n++;}}public long remove() {long temp = queArr[front++];if (front == maxSize) {// 如果头指针等于长度了，头指针重置为0front = 0;}if (!isEmpty()) {n--;}// 为空后n就不再减下去return temp;}public void peekn() {System.out.println("数量" + n);}public boolean isEmpty() {return n == 0;}public boolean isFull() {return n == maxSize;}}public class Queue {public static void main(String[] args) {queueArr arr = new queueArr(5);arr.insert(1);arr.insert(3);arr.insert(4);arr.insert(5);arr.insert(7);arr.insert(9);arr.insert(9);arr.insert(9);arr.insert(9);arr.remove();arr.peekn();while (!arr.isEmpty()) {long n = arr.remove();System.out.print(n + " ");}}}