基础数据结构--栈实现

栈的内容也比较基础，而且有很多博客讲解得很明白，因此此处不再赘述。

代码已经经过检测

#include
#include

#define STACKSIZE 100

//定义元素类型
typedef int elemType;

//定义栈结构
typedef struct stack
{
	elemType *base;
	elemType *top;
	int size;
}stack;

//创建一个栈
stack* createStack()
{
	stack *s = (stack*)malloc(sizeof(stack));
	s->base = (elemType*)malloc(sizeof(elemType)*STACKSIZE);
	s->top = s->base;
	s->size = STACKSIZE;
	return s;
}

//销毁一个栈
void destroyStack(stack* &s)
{
	if(!s) return ;
	else
	{
		if(!s->base) 
		{
			free(s->base);
			s->base = NULL;
			s->top = NULL;
			s->size = 0;
		}
		free(s);
		s = NULL;
	}
}

//获取栈顶元素
int getTop(stack s, elemType &e)
{
	if(!s.base || s.base == s.top || s.size <=0)
		return -1;
	e = *(s.top -1);
	return 1;
}

//压入栈顶
int push(stack &s, elemType e)
{
	if(!s.base || s.size == 0) return -1;
	if(s.top - s.base >= s.size)
	{
		s.base = (elemType*)realloc(s.base,(s.size + STACKSIZE)*sizeof(elemType));
		if(!s.base) return -1;
		s.top = s.base + s.size;
		s.size += STACKSIZE;
	}
	*s.top++ = e;
	return 1;
}

//弹出
int pop(stack &s, elemType &e)
{
	if(!s.base || s.size == 0 || s.base == s.top) return -1;
	e = *--s.top;
	return 1;
}

//打印栈内容
void showStack(stack *s)
{
	if(!s || !s->base || s->size == 0 )
	{
		printf("error: no stack\n");
		return ;
	}
	elemType *temp = s->base;
	while(temp != s->top)
	{
		printf("%d ",*temp);
		temp++;
	}
	printf("\n");
}

//测试代码
int main()
{
	stack *s = createStack();
	push(*s, 4);
	push(*s, 94);
	push(*s, 843);
	push(*s, 12);
	showStack(s);

	elemType e = 3;
	getTop(*s, e);
	printf("e = %d\n",e);

	pop(*s,e);
	pop(*s,e);
	printf("e = %d\n",e);
	showStack(s);

	destroyStack(s);
	showStack(s);

	getchar();
	return 0;
}