[恢]hdu 2080

2011-12-16 12:27:38

地址：http://acm.hdu.edu.cn/showproblem.php?pid=2080

题意：中文，水。

代码：

# include <stdio.h>
# include <math.h>


int main ()
{
    int T ;
    double x1,y1,x2,y2,s1,s2,a1,a2, a ;
    scanf ("%d", &T) ;
    while (T--)
    {
        scanf ("%lf%lf%lf%lf", &x1, &y1, &x2, &y2) ;
        s1 = sqrt(x1*x1+y1*y1) ;
        s2 = sqrt(x2*x2+y2*y2) ;
        a1 = acos(x1/s1)/acos(-1) * 180 ;
        a2 = acos(x2/s2)/acos(-1) * 180 ;
        a = fabs(a1-a2) ;
        printf ("%.2lf\n", a) ;
    }
    
}