```cpp
#include<iostream>
using namespace std;
int main()
{
double i=2,s=1,a=0,b=0;
double l,d=2;
cin>>l;
if(d>=l)
cout<<s;
else
{
for(int j=2;j<=1000;j++)
{
s++;
i=i*0.98;
d=d+i;
if(d>=l)
{
cout<<s;
break;
}
}
}
return 0;
}
```
by LJC00118 @ 2017-10-29 20:27:01
这里一定要用double类型或者float类型，不然2\*0.98的结果会变成1
by LJC00118 @ 2017-10-29 20:28:00