数据结构- 队列实现

数组实现

#include <stdio.h>
#include <stdlib.h>
typedef int E;
typedef struct Queue {
    E *array;
    int capacity;
    int rear,front; //队尾，队首指针
} *ArrayQueue;
_Bool initQueue(ArrayQueue queue) {
    queue->array = malloc(sizeof(E) * 10);
    if(queue->array == NULL ) return 0;
    queue->capacity = 10;
    queue->front = 0;//默认情况下队首和队尾都指向0的位置
    queue->rear = 0;
    return 1;
}
//入队操作
_Bool offerQueue(ArrayQueue queue,E element) {
    if((queue->rear + 1)%queue->capacity == queue->front){ //队满
        return 0;
    }
    queue->rear = (queue->rear + 1)%queue->capacity;//队尾先向后移动一位，注意取余计算才能实现循环
    queue->array[queue->rear] = element;
    return 1;
}
void printQueue(ArrayQueue queue) {//遍历队列
    printf("<<< ");
    int i = queue->front;
    do {
        i = (i+1)%queue->capacity;
        printf("%d ",queue->array[i]);
    } while (i != queue->rear);
    printf("<<<\n");

}
_Bool isEmpty(ArrayQueue queue) {
    return queue->rear == queue->front;//如果相等就是空
}
E pollQueue(ArrayQueue queue) {
    queue->front = (queue->front + 1) % queue->capacity;//队首后移
    return queue->array[queue->front]; //返回出队元素
}

int main() {
    struct Queue queue;
    initQueue(&queue);
    for(int i = 1;i<=9;++i) {
        offerQueue(&queue,i*100);
    }
    printQueue(&queue);
    while(!isEmpty(&queue)) {
        printf("%d ", pollQueue(&queue));
    }
}