使用双链表实现栈

struct NNode

{

    int data;

    struct NNode* prev;

    struct NNode* next;

};

typedef struct NNode* Link;

void DoubleInital();

void DoubllePush(INT);

INT  DoublePop();

void DoubleFree();

Link mover;

INT baseIndex;

void DoubleInital()

{

    mover = NULL;

    baseIndex = 0;

}

void DoubllePush(INT item)

{

    Link x = malloc(sizeof(*x));

    x->data = item;

    

    if (baseIndex == 0)

    {

        x->next = mover;

        x->prev = mover;

        mover = x;

        baseIndex += 1;

        return;

    }

    mover->next = x;

    x->prev = mover;

    x->next = NULL;

    mover = x;

}

INT DoublePop()

{

    if (!mover)

    {

        printf("stacks is empty!!!!");

        return -1;

    }

    INT item = mover->data;

    Link t = mover->prev;

    free(mover);

    mover = t;

    return item;

}