/* queue.h */#ifndef _QUEUE_H#define _QUEUE_Hstruct queue_record;typedef struct queue_record *queue;int is_empty( queue q );int is_full( queue q );queue create_queue( int max_elements );void dispose_queue( queue q );void make_empty( queue q );void enqueue( int x, queue q );int front( queue q );void dequeue( queue q );int front_and_dequeue( queue q );#endif

/* queue.c */#include "queue.h"#include 
     
      #include 
      
       #define MIN_QUEUE_SIZE    5struct queue_record{    int capacity;    int front;    int rear;    int size;    int *array;};voidmake_empty( queue q ){    q->size = 0;    q->front = 1;    q->rear = 0;}intis_empty( queue q ){    return q->size == 0;}int is_full( queue q ){    return q->size == q->capacity;}queuecreate_queue( int max_elements ){    queue q;    if( max_elements < MIN_QUEUE_SIZE )    {        printf("Queue size is too small!\n");        exit(0);    }        q = malloc( sizeof(struct queue_record) );    if(q == NULL)    {        printf("Out of space!\n");        exit(1);    }    q->array = malloc(sizeof(int) * max_elements);    if(q->array == NULL)    {        printf("Out of space!\n");        exit(1);    }    q->capacity = max_elements;    make_empty(q);    return q;}static intsucc( int value, queue q ){    if( ++value == q->capacity )        value = 0;    return value;}voidenqueue( int x, queue q ){    if( is_full( q ) )    {        printf("full queue!\n");        exit(0);    }    else    {        q->size++;        q->rear = succ( q->rear, q );        q->array[q->rear] = x;    }}void dequeue( queue q ){    if( is_empty( q ) )    {        printf("empty queue!\n");        exit(0);    }    else    {        q->size--;        q->front = succ( q->front, q );    }}intfront( queue q ){        if( is_empty( q ) )    {        printf("empty queue!\n");        exit(0);    }    else        return q->array[q->front];}intfront_and_dequeue( queue q ){    int tmp;    if( is_empty( q ) )    {        printf("empty queue!\n");        exit(0);    }    else    {        tmp = q->array[q->front];        q->size--;        q->front = succ( q->front, q );        return tmp;    }}void dispose_queue( queue q ){    if( q != NULL )    {        free(q->array);        free(q);    }}
      
     

/* queue_test.c */#include "queue.h"#include 
     
      intmain(void){    queue q;    int tmp;    int i;        q = create_queue(10);    printf("1 enqueue\n");    enqueue(1, q);    printf("2 enqueue\n");    enqueue(2, q);        printf("3 enqueue\n");    enqueue(3, q);    printf("4 enqueue\n");    enqueue(4, q);    printf("5 enqueue\n");    enqueue(5, q);    printf("\n");    for(i=0; i<5; i++)    {        printf("dequeue %d\n", front_and_dequeue( q ));            }    }
     

测试结果：