栈

堆栈 - 顺序数组实现

堆栈本质上是特殊的线性表，只是对于元素的存取做出了一定的规定

起床时最先穿的内裤，睡觉时确实最后一层才能脱

可见生活中也有很多堆栈性质的例子

定义

struct _node {
    int *data;
    int top;
    int maxSize;
} Node;
typedef struct _node *Stack;

初始化

top = -1 时栈空

top = maxSize - 1 时栈满

Stack createStack(int maxSize) {
    Stack s = (Stack) malloc(sizeof(Node));
    s->data = (int *) malloc(maxSize * sizeof(int));
    s->top = -1;
    s->maxSize = maxSize;
    return s;

}

栈满判断

bool isFull(Stack s) {
    return (s->top == s->maxSize - 1);
}

入栈

bool push(Stack s, int value) {
    if (isFull(s)) {
        printf("栈满");
        return false;
    }
    else {
        s->top++;
        s->data[s->top] = value;
        return true;
    }
}

栈空

bool isEmpty(Stack s) {
    return (s->top == -1);

}

出栈

int pop(Stack s) {
    if (isEmpty(s)) {
        printf("栈空");
        return ERROR;
    }
    else {
        return (s->data[s->top--]);
    }
}

注意事项

取首元素与出栈：一定是先出后取