HDU/2080/main.c
Saturneric 0525ffad24 Add.
2020-09-01 00:48:58 +08:00

31 lines
712 B
C

#include <stdio.h>
#include <math.h>
#define PI 3.1415927
#define ZZS(x) ((x)>=0?1:-1)
#define ABS(x) ((x)>=0?(x):(-(x)))
double agl_ch(double x,double y);
int main(void){
int numbers;
scanf("%d",&numbers);
int i;
double x1,y1,x2,y2;
for(i = 0; i < numbers; i++){
scanf("%lf %lf %lf %lf",&x1,&y1,&x2,&y2);
double a1 = agl_ch(x1, y1), a2 = agl_ch(x2, y2);
double a = ABS(a1 - a2);
if(a > 180) a = 360 - a;
printf("%.2lf\n",a);
}
return 0;
}
double agl_ch(double x,double y){
double agl = atan(y/x) *(180/PI);
if(ZZS(x) > 0 && ZZS(y) < 0) agl = 360 + -ABS(agl);
else if(ZZS(x) < 0 && ZZS(y) > 0) agl = -ABS(agl) + 180;
else if(ZZS(x) < 0 && ZZS(y) < 0) agl = ABS(agl) + 180;
return agl;
}