洛谷p1449后缀表达式题解

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

#define MAXSIZE 100

typedef long ElemType;
typedef struct
{
	ElemType *base;
	ElemType *top;
	int StackSize;
}sqStack;

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

void Push(sqStack *s,ElemType e)
{
	if(s->top-s->base>=s->StackSize)
	{
		exit(0);
	}
	*(s->top)=e;
	s->top++;
}

void Pop(sqStack *s,ElemType *e)
{
	if(s->top==s->base)
	{
		exit(0);
	}
	*e=*--(s->top);
}

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


int main()
{
	sqStack s;
	long sum=0;
	long d,e;
	char c;
	InitStack(&s);
	scanf("%c",&c);
	while(c!='@')
	{
		while(c>='0'&&c<='9')
		{
			sum=sum*10+(c-'0');
			scanf("%c",&c);
		}
		if(c!='-'&&c!='+'&&c!='*'&&c!='/')
		{
			Push(&s,sum);
		}
		
		
		switch(c)
		{
			case '+':
				Pop(&s,&d);
				Pop(&s,&e);
				Push(&s,e+d);
				break;
			case '-':
				Pop(&s,&d);
				Pop(&s,&e);
				Push(&s,e-d);
				break;
			case '*':
				Pop(&s,&d);
				Pop(&s,&e);
				Push(&s,e*d);
				break;
			case '/':
				Pop(&s,&d);
				Pop(&s,&e);
				Push(&s,e/d);
				break;
		}
		sum=0;
		scanf("%c",&c);
	}
	Pop(&s,&e);
	printf("%ld\n",e);
	return 0;
}