include <stdio.h>

include <stdlib.h>

include <ctype.h>

define STACK_INIT_SIZE 20

define STACKINCREMENT 10

define MAXBUFFER 10

typedef double ElemType;
typedef struct
{
ElemType* base;
ElemType* top;
int stackSize;
}sqStack;

void InitStack(sqStack* s)
{
s->base = (ElemType*)malloc(STACK_INIT_SIZE * sizeof(ElemType));
if (!s->base)
exit(0);
s->top = s->base;
s->stackSize = STACK_INIT_SIZE;
}

void Push(sqStack* s, ElemType e)
{
//栈满，追加空间
if (s->top - s->base >= s->stackSize)
{
s->base = (ElemType*)realloc(s->base, (s->stackSize + STACKINCREMENT) * sizeof(ElemType));
if (!s->base)
exit(0);
s->top = s->base + s->stackSize;
s->stackSize += STACKINCREMENT;
}
*(s->top) = e;
s->top++;
}

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

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

}

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

int main(void)
{
sqStack s;
InitStack(&s);
char c;
char str[MAXBUFFER];
double d, e;
int i = 0;

printf("请按逆波兰表达式输入待计算数据，数据与运算符之间用空格隔开，以#为结束标志！\n");
scanf("%c", &c);

while (c != '#')
{
	while (isdigit(c) || c == '.')
	{
		str[i++] = c;
		str[i] = '\0';
		if (i >= 10)
		{
			printf("\n输入数据过大！！！\n");
			return -1;
		}
		scanf("%c", &c);
		if (c == ' ')
		{
			d = atof(str);
			Push(&s, d);
			i = 0;
			break;
		}
	}
	switch (c)
	{
	case '+' :
		Pop(&s, &e);
		Pop(&s, &d);
		Push(&s, d + e);
		break;
	case '-' :
		Pop(&s, &e);
		Pop(&s, &d);
		Push(&s, d - e);
		break;
	case '*' :
		Pop(&s, &e);
		Pop(&s, &d);
		Push(&s, d * e);
		break;
	case '/' :
		Pop(&s, &e);
		Pop(&s, &d);
		if (e != 0)
		{
			Push(&s, d / e);
		}
		else
		{
			printf("\n输入数据有误！！！\n");
			return -1;
		}
			
		break;
	}
	scanf("&c", &c);
}

double f;
Pop(&s, &f);
printf("\n最终结果为 ：%f！！！\n", f);

return 0;

}