POJ P1005,很简单的题目，求出以给定点到原点为半径的半圆的面积，再看够几年侵蚀的（有几个50平方英里）。代码如下：

#include 
    
     #define PI 3.141592int main(){    int n;    float x, y, s;    int i, year;        scanf("%d", &n);    for (i = 1; i <= n; i++){        scanf("%f%f", &x, &y);        s = PI * (x*x + y*y);        year = s / 100 +1;                printf("Property %d: This property will begin eroding in year %d.\n", i, year);    }    puts("END OF OUTPUT.");    system("pause");}