数据结构篇-栈

栈是一种先进后出（LIFO）的线性表，栈规定只能在栈的尾部插入和删除元素；

#include 
#define INISTACKSIZE 20
#define STACKINCREMENT 10
	
	typedef int ElemType;
	typedef struct
	{
		ElemType *base; //栈低指针
		ElemType *top;  //栈顶指针
		int stackSize;  //栈的存储空间大小，栈当前的最大容量

	}sqStack;


	

	
	void InitStack(sqStack *s)
	{
		std::cout << "ini buffern";
		s->base = (ElemType*)malloc(INISTACKSIZE * sizeof(ElemType));
		if (!s->base)
		{
			exit(0);
		}
		s->top = s->base;
		s->stackSize = INISTACKSIZE;
	}

	
	void PushStack(sqStack *s, ElemType e)
	{

		if (s->top - s->base == s->stackSize)
		{
			std::cout << "new buffern";
			s->base = (ElemType*)realloc(s->base, (s->stackSize + STACKINCREMENT) * sizeof(ElemType));
			if (!s->base)
			{
				exit(0);
			}
			s->top = s->base + s->stackSize; //栈重新分配内存后，s->top 重指
			s->stackSize += STACKINCREMENT;
		}

		*(s->top) = e;
		s->top++;

	}

	
	void PopStack(sqStack *s, ElemType *e)
	{
		if (s->top == s->base)
		{
			return;
		}
		s->top--;
		*e = *(s->top);


	}
	
	int GetElemNums(sqStack s)
	{
		return s.top - s.base;
	}

	int main()
	{
		sqStack s;
		InitStack(&s);
		for (int i = 0; i < 51; i++)
		{
			ElemType e = i;
			PushStack(&s, e);
		}
		int cout = GetElemNums(s);
		std::cout << "n" <
			ElemType e = i;
			PopStack(&s, &e);
			std::cout << e << " ";
		}
		cout = GetElemNums(s);
		std::cout << "n" <