栈和队列（数据结构）

栈

1.创建并初始化 

typedef struct Stack{
	char data[MAXSIZE];
	int top;
	}Stack;
	
void InitStack(Stack *s){
	s->top=-1;
}

2.入栈

void InitStack(Stack *s){
	s->top=-1;
}
//Function to push an element into the stack
void Push(Stack *s,char x){
	if(s->top==MAXSIZE-1){
		printf("Stack is full\n");
		exit(1);
	}
	//入栈操作
	s->data[++s->top]=x; //将元素x存储在栈顶指针递增后的位置
}

3.出栈

char Pop(Stack *s){
	if(s->top==-1){
		//printf("Stack is empty\n");
		exit(1);
	}
	//出栈操作
	return s->data[s->top--]; //返回栈顶元素并将栈顶指针递减
}

---

队列

1.创建新队列（结点；首尾指针）

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

typedef struct queue{
	Node *front;
	Node *rear;
}Queue;

2.初始化队列

void InitQueue(Queue *q){
	q->front = q->rear = (Node *)malloc(sizeof(Node));
	q->front->next = NULL;
}

3.入队 

void push(Queue *q, int x){
	Node *p = (Node *)malloc(sizeof(Node));
	p->data = x;
	p->next = NULL; //新结点指针域为空
	q->rear->next = p; //尾插法
	q->rear = p; //更新尾指针
}

4.出队

int pop(Queue *q){
	if(q->front == q->rear) {
    printf("Invalid\n");
	return -1; //队列为空
	}
	Node *p = q->front->next;
	int x = p->data;
	q->front->next = p->next;
	if(q->rear == p) q->rear = q->front; //若队列中只有一个元素，删除后更新尾指针
	free(p);
	return x;
}

5.求队列长度 

int size(Queue *q){
	int Size = 0;
	Node *p = q->front->next;
	while(p){
		Size++;
		p = p->next;
	}
	return Size;
}