#include<stdio.h>
 
#define SIZE 5
int queue[SIZE];
int head, tail;
 
void enqueue(int value);
int dequeue(void);
 
int main(void)
{
head = tail = 0; 
 int i;
 
 enqueue(1);
 enqueue(2);
 dequeue();
 enqueue(3);
 dequeue();
 enqueue(4);
 enqueue(5);
 dequeue();
 enqueue(6);
 
 
 
 
 for(i=0; i<SIZE; i++){
 	printf("queue[%d]=%d\n", i, queue[i] );
 }
 
 return 0;
}
 
 
void enqueue(int value)
{
 
    if ((tail + 1) % SIZE == head) {
        return;
    }
 
    queue[tail] = value;
 
    tail = (tail + 1) % SIZE;
}
 
 
int dequeue(void)
{
    int value;
 
 
    if (head == tail) {
 
        return 0; 
    }
 
 
    value = queue[head];
 
     queue[head] = 0;
 
    head = (head + 1) % SIZE;
 
 
    return value;
}

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cXVldWVbMF09NgpxdWV1ZVsxXT0wCnF1ZXVlWzJdPTAKcXVldWVbM109NApxdWV1ZVs0XT01

queue[0]=6
queue[1]=0
queue[2]=0
queue[3]=4
queue[4]=5