poj1005 I Think I Need a Houseboat

这题目只要读懂了意思就好做了，先求出来（0.0）到(x.y)的距离为r，然后求出来以r为半径的半圆的面积，然后再用这个面积除以50,再向上取整就可以啦。

 #include <stdio.h>
 #include <math.h>
 #include <stdlib.h>
 #define  eps 0.000000001
 #define  pie 3.1415926
 int main(){
     int t;
     double res;
     double area;
     double r;
     double x,y;
     int cnt=;
     scanf("%d",&t);
     while(t--){
         scanf("%lf%lf",&x,&y);
         r=sqrt( x*x+y*y );
         area=(pie*r*r)/;
         res=area/50.0;
         printf("Property %d: This property will begin eroding in year %d.\n",cnt++,(int)ceil(res));
     }
     printf("END OF OUTPUT.\n");
     return ;
 }