C++顺序队列

#include <iostream>using namespace std;struct SqQueue{    char data[20];    int front,rear;};bool SqQueueEmpty(SqQueue q){    return (q.front==q.rear);}bool enQueue(SqQueue& q,char e){    if(q.rear==20-1)        return false;    q.rear++;    q.data[q.rear]=e;    return true;}bool deQueue(SqQueue& q,char& e){    if(q.front==q.rear)        return false;    q.front++;    e=q.data[q.front];    return true;}int main(){    SqQueue q;    q.front=q.rear=-1;    char e,a[5]= {'a','b','c','d'};    for(int i=0; i<5; i++)    {        if(!enQueue(q,a[i]))            break;    }    if(SqQueueEmpty(q))        cout<<"空队。\n";    else        cout<<"非空队。\n";    while(deQueue(q,e))    {        cout<<e<<' ';    }    return 0;}