C语言实现循环队列

循环队列

1、循环队列的创建

#define N 5
typedef int data_type;
typedef struct{
 data_type buf[N];
 int front;
 int rear;
}loop_queue;

loop_queue *create_loop_queue(){

loop_queue * lq=(loop_queue*)malloc(sizeof(loop_queue));
if(NULL==lq){
printf("malloc fail!\n");
}
memset(lq,0,sizeof(loop_queue));
return lq;
}

2、判空

int is_empty(loop_queue *lq){
return lq->front==lq->rear;
}

3、判满

int is_full(loop_queue *lq){

return lq->front==(lq->rear+1)%N;
}

4、入队

void in_queue(loop_queue *lq,data_type data){

lq->buf[lq->rear]=data;
lq->rear=(lq->rear+1)%N;
}

5、出队

data_type out_queue(loop_queue *lq){

data_type data=lq->buf[lq->front];

lq->front=(lq->front+1)%N;
return data;
}