C语言数据结构队列

#include<stdio.h>
#include<stdlib.h>

struct Node {
int data; 
Node *next;
};

struct Queue {
Node* head;
Node* rear;
};

Queue* creatQueue() {
Queue *Q = new Queue;
Node *node = (Node*)malloc(sizeof(Node)); 
node->next = NULL;
Q->head = Q->rear = node;
return Q;
}

void enQueue(Queue *Q, int d) {
Node *node = (Node*)malloc(sizeof(Node));
node->data = d;
node->next = NULL;
Q->rear->next = node;
Q->rear = node;
}

void output(Queue *Q) {
int data;
if (Q->head == Q->rear) {
printf("队列下溢！");
}
Node *node = Q->head->next;
data = node->data;
Q->head->next = node->next;
if (node->next == NULL) {
Q->rear = Q->head;
}
free(node);
}

void printQueue(Queue *Q) {
Node *node = Q->head->next;
puts("队列成员如下\n\n");
while (node != NULL) {
printf("%d\n", node->data);
node = node->next;
}
putchar('\n');
}

void destroyQueue(Queue *Q) { 
Node *node;
while (Q->head) {
node = Q->head->next;
free(Q->head);
Q->head = node;
}
free(Q);
}

int main(int argc,char** argv) {
int select,d;
Queue *Q = creatQueue();
while (1) 
{
puts("1,入队\n2,出队\n3,遍历\n0,退出\n\n请输入操作号：");
scanf("%d", &select);
switch (select) 
{
case 1:
puts("请输入需要入队的数字：");
scanf("%d", &d);
enQueue(Q, d);
break;
case 2:
output(Q);
break;
case 3:
printQueue(Q);
break;
case 0: 
printf("程序已退出\n");
exit(1);
break;
default:
puts("输入错误！\n");
break;
}

}

destroyQueue(Q);

}