poj-1005-l tanink i need a houseboat

Description

Fred Mapper is considering purchasing some land in Louisiana to build his house on. In the process of investigating the land, he learned that the state of Louisiana is actually shrinking by 50 square miles each year, due to erosion caused by the Mississippi River. Since Fred is hoping to live in this house the rest of his life, he needs to know if his land is going to be lost to erosion.

After doing more research, Fred has learned that the land that is being lost forms a semicircle. This semicircle is part of a circle centered at (0,0), with the line that bisects the circle being the X axis. Locations below the X axis are in the water. The semicircle has an area of 0 at the beginning of year 1. (Semicircle illustrated in the Figure.)

Input

The first line of input will be a positive integer indicating how many data sets will be included (N). Each of the next N lines will contain the X and Y Cartesian coordinates of the land Fred is considering. These will be floating point numbers measured in miles. The Y coordinate will be non-negative. (0,0) will not be given.

Output

For each data set, a single line of output should appear. This line should take the form of: “Property N: This property will begin eroding in year Z.” Where N is the data set (counting from 1), and Z is the first year (start from 1) this property will be within the semicircle AT THE END OF YEAR Z. Z must be an integer. After the last data set, this should print out “END OF OUTPUT.”

Sample Input

2
1.0 1.0
25.0 0.0

Sample Output

Property 1: This property will begin eroding in year 1.
Property 2: This property will begin eroding in year 20.
END OF OUTPUT.

Hint

1.No property will appear exactly on the semicircle boundary: it will either be inside or outside.
2.This problem will be judged automatically. Your answer must match exactly, including the capitalization, punctuation, and white-space. This includes the periods at the ends of the lines.
3.All locations are given in miles.

题目大意：

题目：密西西比河岸某处陆地因为河水侵蚀，每年陆地面积都在减少，每年减少50平方英里，减少的陆地面积呈半圆形，即该半圆形面积以每年50平方英里的速度增长。在第一年初时，该半圆形面积为0，半圆形的圆心坐标为（0,0），现在的任务是给定一个坐标，求出该坐标在哪一年年底会被河水侵蚀。假设给定的坐标到圆心的距离不会等于半圆的半径。

输入：第一行输入坐标个数，第二行开始输入坐标，每个坐标占一行，每个坐标由横坐标和纵坐标组成，坐标值为浮点数，单位为英里。

输出：输出该坐标会在哪一年年底开始被河水侵蚀。对应每个坐标输出一行，输出结束后输出 “END OF OUTPUT.”

#include<iostream>
using namespace std;
const double pi=3.1415926;
int main()
{
    int n;
    cin>>n;

    for(int i=1;i<=n;i++)
    {
    double len,wid;
    double m;
    int mm=0;
    cin>>len>>wid;
    m=pi*(len*len+wid*wid)/2;。//求出整个岛消失的面积
    mm=m/50+1;

    cout<<"Property "<<i<<": This property will begin eroding in year "<<mm<<"."<<endl;
    if(i==n)cout<<"END OF OUTPUT.";

    }

    return 0;
}