///////////////////////////////////////// 
//  
// author: kangquan2008@csdn 
// 
///////////////////////////////////////// 
#include <stdio.h> 
#include <stdlib.h> 
#include <stdbool.h> 
 
#define QUEUE_SIZE 10 
#define EN_QUEUE 1 
#define DE_QUEUE 2 
#define EXIT   3 
 
typedef int  Item; 
typedef struct QUEUE{ 
 
  Item * item; 
  int front; 
  int tear; 
 
}Queue; 
 
int init_queue(Queue * queue) 
{ 
  queue->item = malloc(QUEUE_SIZE * sizeof(Item)); 
  if(!queue->item) 
  { 
    printf("%s\n","Alloc failed,not memory enough"); 
    exit(EXIT_FAILURE); 
  } 
 
  queue->front = queue->tear = 0; 
 
  return 1; 
} 
 
int en_queue(Queue * queue, Item item) 
{ 
  if((queue->tear+1) % QUEUE_SIZE == queue->front) 
  { 
    printf("%s\n","The queue is full"); 
    return -1; 
  } 
 
  queue->item[queue->tear] = item; 
  queue->tear = (queue->tear + 1) % QUEUE_SIZE; 
 
  return 1; 
} 
 
int de_queue(Queue * queue, Item * item) 
{ 
  if(queue->front == queue->tear) 
  { 
    printf("%s\n","The queue is empty"); 
    return -1; 
  } 
 
  (*item) = queue->item[queue->front]; 
  queue->front = (queue->front + 1) % QUEUE_SIZE; 
 
  return 1; 
} 
 
int destroy_queue(Queue * queue) 
{ free(queue->item); 
} 
 
int main() 
{ 
  Queue que; 
  init_queue(&que); 
  int elem; 
  bool flag = true; 
  while(flag) 
  { 
    int choice; 
    printf("1 for en_queue,2 for de_queue,3 for exit\r\nplease input:"); 
    scanf("%d",&choice); 
 
    switch((choice)) 
    { 
      case EN_QUEUE: 
        printf("input a num:"); 
        scanf("%d",&elem); 
        en_queue(&que,elem); 
        break; 
      case DE_QUEUE: 
        if(de_queue(&que,&elem) == 1) 
          printf("front item is:%d\n",elem); 
        break; 
      case EXIT: 
        flag = false; 
        break; 
      default: 
        printf("error input\n"); 
        break; 
    } 
  } 
 
  destroy_queue(&que); 
  return 0; 
} 

#include <stdio.h> 
#include <assert.h> 
#define QueueSize 100 
typedef char datatype; 
//队列的数据元素 
typedef struct 
{ 
   int front; 
   int rear; 
   int count; //计数器，用来记录元素个数 
   datatype data[QueueSize]; //数据内容 
}cirqueue; 
//置空队 
void InitQueue(cirqueue *q) 
{ 
   q->front = q->rear = 0; 
   q->count = 0; 
} 

//判断队满 
int QueueFull(cirqueue *q) 
{ 
   return (q->count == QueueSize); 
} 

//判断队空 
int QueueEmpty(cirqueue *q) 
{ 
   return (q->count == 0); 
} 

//入队 
void EnQueue(cirqueue *q, datatype x) 
{ 
   assert(QueueFull(q) == 0); //q满，终止程序 
 
   q->count++; 
   q->data[q->rear] = x; 
   q->rear = (q->rear + 1)%QueueSize; //循环队列设计，防止内存浪费 
} 

//出队 
datatype DeQueue(cirqueue *q) 
{ 
   datatype temp; 
 
   assert(QueueEmpty(q) == 0);//q空，则终止程序，打印错误信息 
 
   temp = q->data[q->front]; 
   q->count--; 
   q->front = (q->front + 1)%QueueSize; 
   return temp; 
}