用C语言实现队列的①创建、②入队、③出队、④取队首元素、⑤判断队列是否为空
时间: 2023-10-24 11:08:07 浏览: 62
#include <stdio.h>
#include <stdlib.h>
#define MAX_SIZE 100
typedef struct {
int data[MAX_SIZE];
int front, rear;
} Queue;
void init_queue(Queue *q) {
q->front = q->rear = -1;
}
int is_empty(Queue *q) {
return q->front == -1 && q->rear == -1;
}
int is_full(Queue *q) {
return (q->rear + 1) % MAX_SIZE == q->front;
}
void enqueue(Queue *q, int x) {
if (is_full(q)) {
printf("Queue is full.\n");
return;
}
if (is_empty(q)) {
q->front = q->rear = 0;
} else {
q->rear = (q->rear + 1) % MAX_SIZE;
}
q->data[q->rear] = x;
}
int dequeue(Queue *q) {
if (is_empty(q)) {
printf("Queue is empty.\n");
return -1;
}
int x = q->data[q->front];
if (q->front == q->rear) {
q->front = q->rear = -1;
} else {
q->front = (q->front + 1) % MAX_SIZE;
}
return x;
}
int front(Queue *q) {
if (is_empty(q)) {
printf("Queue is empty.\n");
return -1;
}
return q->data[q->front];
}
int main() {
Queue q;
init_queue(&q);
enqueue(&q, 1);
enqueue(&q, 2);
enqueue(&q, 3);
printf("Front element: %d\n", front(&q));
printf("Dequeued element: %d\n", dequeue(&q));
printf("Dequeued element: %d\n", dequeue(&q));
printf("Front element: %d\n", front(&q));
enqueue(&q, 4);
enqueue(&q, 5);
while (!is_empty(&q)) {
printf("Dequeued element: %d\n", dequeue(&q));
}
return 0;
}