#include <stdio.h>
#include <stdlib.h>

struct Stack;
typedef struct Stack *Stack;
typedef int ElementType;

#define EmptyOTS -1
#define MinStackSize 5

//棧的資料結構
struct Stack
{
    int Capacity;
    int TopOfStack;
    int *Array;
};

// 申請兩次記憶體，第一次為棧的Capacity和TopOfStack申請，第二次為Array申請
Stack CreateStack(int
 
 MaxElements)
{
    Stack S;

    if (MaxElements < MinStackSize)
    {
        printf("stack size if too small!\n");
        return NULL;
    }
    // 第一次申請記憶體
    S = malloc(sizeof(struct Stack));
    if (S == NULL)
    {
        printf("Stack malloc failed!\n");
        return NULL;
    }
    // 為array申請記憶體
 

    S->Array = malloc(sizeof(ElementType) * MaxElements);
    if (S->Array == NULL)
    {
        printf("S->Array malloc failed!\n");
        return NULL;
    }

    // 設定最大長度和初始化棧頂
    S->Capacity = MaxElements;
    S->TopOfStack = EmptyOTS;

    return S;
}

// 對應建立棧時申請的記憶體，對應釋放記憶體，注意釋放順序
 

void FreeStack(Stack S)
{
    if (S != NULL)
    {
        free(S->Array);
        free(S);
    }
}

// 判斷棧是否為滿棧
int IsFull(Stack S)
{
    return S->TopOfStack == S->Capacity;
}

// 判斷棧是否為空棧
int IsEmpty(Stack S)
{
    return S->TopOfStack == EmptyOTS;
}

// 新增元素
void Push(ElementType X, Stack S)
{
    if (IsFull(S))
    {
        printf("stack is full\n");
        return;
    }
    S->TopOfStack++;
    S->Array[S->TopOfStack] = X;
}

// pop操作無需free
void Pop(Stack S)
{
    if (IsEmpty(S))
    {
        printf("stack is empty, cann't pop\n");
        return;
    }
    S->TopOfStack--;
}

//取棧頂的元素
ElementType Top(Stack S)
{
    if (IsEmpty(S))
    {
        printf("empty stack\n");
        return 0;
    }
    return S->Array[S->TopOfStack];
}

// 列印棧的所有元素，從棧底向棧頂列印
void PrintStack(Stack S)
{
    if (IsEmpty(S))
    {
        printf("stack is empty\n");
        return;
    }
    for (int i = 0; i <= S->TopOfStack; i++)
    {
        printf("%d\n", S->Array[i]);
    }
}

int main(int argc, char const *argv[])
{
    Stack S = CreateStack(5);
    for (int i = 1; i < 5; i++)
    {
        Push(i, S);
    }
    PrintStack(S);
    Pop(S);
    PrintStack(S);
    printf("%d\n", Top(S));
    return 0;
}