> #include <iostream>
> #include <cstdio>
> using namespace std;
> int main()
> {
>    int i=0,n,N;
>    double x,y;
>    cin>>n;
>    for(int j=0;j<n;j++)
>    {
> 	   cin>>x>>y;
> 	   i++;
> 	   N=(x*x+y*y)*3.1416/50;
> 	   N=(int)(N+0.5);
> 	   printf("Property %d: This property will begin eroding in year %d.\n",i,N+1);
>    }
>    cout<<"END OF OUTPUT."<<endl;
>    return 0;
> }
这是半圆，面积要除以2，而且结果也不应该是四舍五入