c++ strchr函数_strchr函数返回_模拟实现strchr函数(30)

lat1*=pi/180,lat2*=pi/180;

returnacos(cos(lat1)*cos(lat2)*cos(dlng)sin(lat1)*sin(lat2));

}

double line_dist(double r,doublelng1,double lat1,double lng2,double lat2){

doubledlng=fabs(lng1-lng2)*pi/180;

while(dlng>=pipi)

dlng-=pipi;

if(dlng>pi)

dlng=pipi-dlng;

lat1*=pi/180,lat2*=pi/180;

returnr*sqrt(2-2*(cos(lat1)*cos(lat2)*cos(dlng)sin(lat1)*sin(lat2)));

}

inline double sphere_dist(double r,doublelng1,double lat1,double lng2,double lat2){

returnr*angle(lng1,lat1,lng2,lat2);

}

#include <math.h>

struct point{double x,y;};

struct line{point a,b;};

double distance(point p1,point p2){

returnsqrt((p1.x-p2.x)*(p1.x-p2.x)(p1.y-p2.y)*(p1.y-p2.y));

}

point intersection(line u,line v){

pointret=u.a;

doublet=((u.a.x-v.a.x)*(v.a.y-v.b.y)-(u.a.y-v.a.y)*(v.a.x-v.b.x))

/((u.a.x-u.b.x)*(v.a.y-v.b.y)-(u.a.y-u.b.y)*(v.a.x-v.b.x));

ret.x=(u.b.x-u.a.x)*t;

ret.y=(u.b.y-u.a.y)*t;

returnret;

}

point circumcenter(point a,point b,pointc){

lineu,v;

u.a.x=(a.xb.x)/2;

u.a.y=(a.yb.y)/2;

u.b.x=u.a.x-a.yb.y;

u.b.y=u.a.ya.x-b.x;

v.a.x=(a.xc.x)/2;

v.a.y=(a.yc.y)/2;

v.b.x=v.a.x-a.yc.y;

v.b.y=v.a.ya.x-c.x;

returnintersection(u,v);

}

point incenter(point a,point b,point c){

lineu,v;

doublem,n;

u.a=a;

m=atan2(b.y-a.y,b.x-a.x);

n=atan2(c.y-a.y,c.x-a.x);

u.b.x=u.a.xcos((mn)/2);

u.b.y=u.a.ysin((mn)/2);

v.a=b;

m=atan2(a.y-b.y,a.x-b.x);

n=atan2(c.y-b.y,c.x-b.x);

v.b.x=v.a.xcos((mn)/2);

v.b.y=v.a.ysin((mn)/2);

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