队列 数组实现

#include <iostream>
using namespace std;

#define MAX 100
typedef struct  //循环体结构体
{
    int a[MAX];
    int front;
    int rear;
}CirQueue;

void init(CirQueue &q)  //初始化 front = rear = 0
{
    q.front = q.rear = 0;
}

void enqueue(CirQueue &q,int &x)  //进队 a[rear] = x, rear = rear + 1 % max;
{
    q.a[q.rear] = x;
    q.rear = (q.rear + 1) % MAX;
}

int dequeue(CirQueue &q)       //出队 return a[front]; front = front + 1 % max;
{
    int t = q.a[q.front];
    q.front = (q.front + 1) % MAX;
    return t;
}

bool isEmpty(CirQueue &q)     //队空 队首等于队尾 rear == front
{
    return q.rear = q.front;
}

bool ifFull(CirQueue &q)  //队满  队尾再进一个元素就变队头 即：front == (rear + 1) % MAX;
{
    if((q.rear + 1)%MAX == q.front)
        return true;
    else
        return false;
}

int size(CirQueue &q) // 队大小 (rear - front + max) % max
{
    return (q.rear - q.front + MAX) % MAX;
}

int main()
{
    CirQueue q;
    init(q);
    int n;
    cin>>n;
    for(int i = 0;i<n;i++)
        enqueue(q, i);
    cout<<size(q)<<endl;
    for(int i = 0;i<n;i++)
    {
        cout<<q.front<<" ";
        dequeue(q);
    }
    cout<<endl<<size(q)<<endl;
    
    return 0;
}