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=1;
    scanf("%d",&t);
    while(t--){
        scanf("%lf%lf",&x,&y);
        r=sqrt( x*x+y*y );
        area=(pie*r*r)/2;
        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 0;
}