c++ strchr函数_strchr函数返回_模拟实现strchr函数(28)

/((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 intersection(point u1,point u2,pointv1,point v2){

pointret=u1;

doublet=((u1.x-v1.x)*(v1.y-v2.y)-(u1.y-v1.y)*(v1.x-v2.x))

/((u1.x-u2.x)*(v1.y-v2.y)-(u1.y-u2.y)*(v1.x-v2.x));

ret.x=(u2.x-u1.x)*t;

ret.y=(u2.y-u1.y)*t;

returnret;

}

point ptoline(point p,line l){

pointt=p;

t.x=l.a.y-l.b.y,t.y=l.b.x-l.a.x;

returnintersection(p,t,l.a,l.b);

}

point ptoline(point p,point l1,point l2){

pointt=p;

t.x=l1.y-l2.y,t.y=l2.x-l1.x;

returnintersection(p,t,l1,l2);

}

double disptoline(point p,line l){

returnfabs(xmult(p,l.a,l.b))/distance(l.a,l.b);

}

double disptoline(point p,point l1,pointl2){

returnfabs(xmult(p,l1,l2))/distance(l1,l2);

}

double disptoline(double x,double y,doublex1,double y1,double x2,double y2){

returnfabs(xmult(x,y,x1,y1,x2,y2))/distance(x1,y1,x2,y2);

}

point ptoseg(point p,line l){

pointt=p;

t.x=l.a.y-l.b.y,t.y=l.b.x-l.a.x;

if(xmult(l.a,t,p)*xmult(l.b,t,p)>eps)

returndistance(p,l.a)<distance(p,l.b)?l.a:l.b;

returnintersection(p,t,l.a,l.b);

}

point ptoseg(point p,point l1,point l2){

pointt=p;

t.x=l1.y-l2.y,t.y=l2.x-l1.x;

if(xmult(l1,t,p)*xmult(l2,t,p)>eps)

returndistance(p,l1)<distance(p,l2)?l1:l2;

returnintersection(p,t,l1,l2);

}

double disptoseg(point p,line l){

pointt=p;

t.x=l.a.y-l.b.y,t.y=l.b.x-l.a.x;

if(xmult(l.a,t,p)*xmult(l.b,t,p)>eps)

returndistance(p,l.a)<distance(p,l.b)?distance(p,l.a):distance(p,l.b);

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