有输出每一步的代码，类型转换的数字很诡异而且运算不准，总是会多一个0.000009

#include<stack>
#include<iostream>
#include<string>
using namespace std;
double a,b;
string s;
stack <double>q;
int intn(string x)
{
    int num;
    for(int i=0;i<x.size();i++)
    {
        num=num*10+(x[i]-'0');
    }
    cout<<num<<endl;
    return num;
}
int main(){
	while(cin>>s)
	{
	    if('0'<=s[0]&&s[0]<='9')q.push(intn(s));
	    if(s=="+")
	    {
	        a=q.top();q.pop();
	        b=q.top();q.pop();
	        q.push(a+b);
	        printf("%.6lf",q.top());
	        cout<<endl;
	        
	    }
	     if(s=="+")
	    {
	        a=q.top();q.pop();
	        b=q.top();q.pop();
	        q.push(b-a);
	        printf("%.6lf",q.top());
	        cout<<endl;
	    }
	    if(s=="-")
	    {
	        a=q.top();q.pop();
	        b=q.top();q.pop();
	        q.push(b/a);
	        printf("%.6lf",q.top());
	        cout<<endl;
	    }
	    if(s=="*")
	    {
	        a=q.top();q.pop();
	        b=q.top();q.pop();
	        q.push(b*a);
	        printf("%.6lf",q.top());
	        cout<<endl;
	    }
	}
	printf("%.6lf",q.top());
	return 0;
}