HDU 1237 简单计算器（stack）

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<cmath>
#include<queue>
#include<stack>
#include<vector>

#define L(x) (x<<1)
#define R(x) (x<<1|1)
#define MID(x,y) ((x+y)>>1)

#define eps 1e-8
using namespace std;
#define N 10005

int main()
{
	int i;
	char c,cc;
	double a,b;

	while(~scanf("%lf%c",&a,&c))
	{
       if(fabs(a-0)<eps&&c=='\n')
		break;

		if(c=='\n')
		{
			printf("%.2lf\n",a);
			continue;
		}

	    stack<double>q;
	    q.push(a);

          scanf("%c%lf",&c,&a);
          if(c=='+')
		        q.push(a);
		   else
		      if(c=='-')
		        q.push(a*(-1));
		   else
		  {
			 double cur=q.top();
			 q.pop();
			 if(c=='*')
			  q.push(cur*a);
			 else
			  q.push(cur/a);
		  }

        while(scanf("%c",&c))
		{
			if(c=='\n') break;
			scanf("%c%lf",&c,&a) ;
			if(c=='+')
		        q.push(a);
		   else
		      if(c=='-')
		        q.push(a*(-1));
		   else
		  {
			 double cur=q.top();
			 q.pop();
			 if(c=='*')
			  q.push(cur*a);
			 else
			  q.push(cur/a);
		  }
		}

		double ans=0;
		while(!q.empty())
		{
			ans+=q.top();
			q.pop();
		}
       printf("%.2lf\n",ans);
	}
   return 0;

}