Calculate Geometry Template

Since I'm in charge of calculating geometry, I'll brush some more questions. WW

Template adapted from Rujia

Point, line Base section:

structpoint{Doublex, y; Point (Doublex=0,Doubley=0): X (x), Y (y) {}};typedef point Vector; Point Read () {DoubleX, Y;SCANF ("%LF%LF", &x, &y);returnPoint (x, y);} Vectoroperator+ (vector A, vector B) {returnVector (a.x + b.x, A.Y +b.y); }vectoroperator-(vector A, vector B) {returnVector (a.x-b.x, A.Y-b.y); }vectoroperator* (Vector A,DoubleP) {returnVector (A.x*p, a.y*p); }vectoroperator/(Vector A,DoubleP) {returnVector (a.x/p, a.y/p); }Double    operator* (vector A, vector B) {returna.x*b.x + a.y*b.y;}//dot ProductDouble    operator^ (vector A, vector B) {returna.x*b.y-a.y*b.x;}//Cross ProductBOOL    operator< (Constpoint& A,Constpoint& b) {returna.x < b.x | | (a.x = = b.x && A.y <b.y); }intDCMP (Doublex) {if(Fabs (x) < EPS)return 0;Else returnX <0? -1:1; }BOOL    operator==(Constpoint& A,Constpoint& b) {returnDCMP (a.x-b.x) = =0&& dcmp (a.y-b.y) = =0; }DoubleLength (Vector A) {returnsqrt (a*a); }//the modulus of a vectorDoubleAngle (vector A, vector B) {returnACOs (A*b/length (A)/Length (B)); }//the angle of the vector, the return value is radiansDoubleAREA2 (Point A, point B, point C) {return(b-a) ^ (c-a); }//The direction area of the vector ab Fork by ACVector vrotate (vector A,Doublerad) {returnVector (A.x*cos (RAD)-A.y*sin (RAD), A.x*sin (RAD) + A.y*cos (RAD));}//vector A rotates rad radiansPoint Protate (Point A, point B,Doublerad) {returnA + vrotate (B-a, RAD);}//Rotate B Point around a point to rad radiansVector Normal (vector A) {DoubleL = Length (A);returnVector (-a.y/l, a.x/l);}//ask vector A to rotate the unit normal vector of 90° to the left, make sure a is not a 0 vector before callingPoint getlineintersection/*to make sure that the two lines have a unique intersection before calling the line intersection.*/(Point P, Vector v, point Q, Vector W) {Doublet = (w^ (p-q))/(V^W);returnP + v*t;}//You can customize the fractional class when the accuracy requirement is extremely highDoubleDistancetoline/*distance from P-point to straight-line AB*/(Point P, point A, point B) {Vector V1 = b-a, v2 = p-a;returnFabs (V1^V2)/Length (v1);}//no absolute value is a forward distanceDoubleDistancetosegment/*Point-to-line distance*/(Point P, point A, point B) {if(a==b)returnLength (P-A); Vector v1=b-a,v2=p-a,v3=p-C; if(DCMP (V1*V2) <0)returnLength (v2);Else    if(DCMP (V1*V3) >0)returnLength (v3);Else    returnFabs (V1*V2)/Length (v1);} Point Getlineprojection/*a projection of points on a straight line*/(Point P, point A, point B) {Vector v=b-A; returnA+v* ((v* (P-A))/(v*v));}BOOLSs_is/*Line segment "Specification" intersection decision*/(Point A1, Point A2, point B1, point B2) {Doublec1= (A2-A1) ^ (B1-A1), c2= (A2-A1) ^ (b2-A1); Doublec3= (B2-B1) ^ (A1-B1), c4= (B2-B1) ^ (a2-B1); returnDCMP (C1) *dcmp (C2) <0&& dcmp (C3) *dcmp (C4) <0;}BOOLOnsegment/*determines whether a point is on a line segment (with endpoints)*/(Point p,point a1,point A2) {Vector V1=a1-p,v2=a2-Q; if(dcmp (v1^v2) = =0&& min (a1.x,a2.x) <=p.x && P.x<=max (a1.x,a2.x) && min (a1.y,a2.y) <=p.y && p.y& Lt;=max (A1.Y,A2.Y))return true; return false;}BOOLIntri/*determine if a point is inside a triangle*/(Point P, point A,point b,point c) {if(DCMP (Fabs (c-a) ^ (c-b))-fabs ((p-a) ^ (p-b))-fabs ((p-b) ^ (p-c))-fabs ((p-a) ^ (p-c)) = =0)return true; return false;}DoublePolygonarea/*to find the polygon area, note that the convex hull p number starts at 0.*/(Point *p,intN) {    DoubleAns =0.0;  for(intI=1; i<n-1; i++) ans+ = (p[i]-p[0]) ^ (p[i+1]-p[0]); returnans/2;}BOOLCrossofsegandline/*to determine if a segment intersects a line*/(Point a1,point a2,point b1,vector B2) {if(Onsegment (B1,A1,A2) | | Onsegment (B1+B2,A1,A2))return true; returnDCMP (b2^ (A1-B1)) *dcmp (b2^ (A2-B1)) <0;}

Calculate Geometry Template