C语言指针实现简单栈

stack:FILO
操作:push 向栈顶压入一个元素
pop 从栈顶弹出元素，pop一个空栈返回-1

节点结构体：

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

栈结构体：

typedef struct linkedlist{    Node *head;    Node *tail;} Stack;

操作：

//初始化栈void initializeStack(Stack *stack){    stack->head = NULL;    stack->tail = NULL;}//向栈顶压入元素void push(Stack *stack, int data){    Node *node = (Node *) malloc(sizeof(Node));    node->data = data;    if (stack->head == NULL)    {        stack->tail = node;        node->next = NULL;    }    else    {        node->next = stack->head;    }    stack->head = node;}//弹出栈顶元素并返回栈顶元素的值int pop(Stack *stack){    int data;    Node *node = stack->head;    if (stack->head == NULL)    {        data = -1;    }    else if (node == stack->tail)    {        data = stack->head->data;        stack->head = stack->tail = NULL;        free(node);    }    else    {        data = stack->head->data;        stack->head = stack->head->next;        free(node);    }    return data;}//释放所有未释放的空间void freeAll(Stack *stack){    while(pop(stack)!=-1);    printf("\nFree Complete!\n");    return;}int main(){    Stack stack;    initializeStack(&stack);    push(&stack, 1);    push(&stack, 2);    push(&stack, 3);    push(&stack, 4);    push(&stack, 5);    printf("%d ", pop(&stack));    printf("%d \n", pop(&stack));  //5 4    //1 2 3 <- top    push(&stack, 11);    push(&stack, 23);    push(&stack, 323);  //1 2 3 11 23 323    printf("%d ", pop(&stack));    printf("%d ", pop(&stack));    printf("%d ", pop(&stack));    printf("%d ", pop(&stack));    printf("%d ", pop(&stack));    printf("%d ", pop(&stack));    printf("%d \n", pop(&stack));    freeAll(&stack);    return 0;}

小结：栈的实现基于链表，push操作相当于addHead