uva-573 反思一下，好好读题

#include<iostream>using namespace std;double ans,t,H,D,U,F;int main(){    while(cin>>H>>U>>D>>F&&H)    {        ans=0.0;t=0;        F=F*U/100.0;        while(ans>=0.0)        {            t++;            if(U>0)ans+=U;            if(ans>H)break;            ans-=D;            U-=F;        }        if(ans<0)            cout<<"failure on day "<<t<<endl;        else            cout<<"success on day "<<t<<endl;    }}