c++ strchr函数_strchr函数返回_模拟实现strchr函数(27)

returnxmult(l.a,p1,l.b)*xmult(l.a,p2,l.b)<-eps;

}

int opposite_side(point p1,point p2,pointl1,point l2){

returnxmult(l1,p1,l2)*xmult(l1,p2,l2)<-eps;

}

int parallel(line u,line v){

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

}

int parallel(point u1,point u2,pointv1,point v2){

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

}

int perpendicular(line u,line v){

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

}

int perpendicular(point u1,point u2,pointv1,point v2){

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

}

int intersect_in(line u,line v){

if(!dots_inline(u.a,u.b,v.a)||!dots_inline(u.a,u.b,v.b))

return!same_side(u.a,u.b,v)&&!same_side(v.a,v.b,u);

returndot_online_in(u.a,v)||dot_online_in(u.b,v)||dot_online_in(v.a,u)||dot_online_in(v.b,u);

}

int intersect_in(point u1,point u2,pointv1,point v2){

if(!dots_inline(u1,u2,v1)||!dots_inline(u1,u2,v2))

return!same_side(u1,u2,v1,v2)&&!same_side(v1,v2,u1,u2);

returndot_online_in(u1,v1,v2)||dot_online_in(u2,v1,v2)||dot_online_in(v1,u1,u2)||dot_online_in(v2,u1,u2);

}

int intersect_ex(line u,line v){

returnopposite_side(u.a,u.b,v)&&opposite_side(v.a,v.b,u);

}

int intersect_ex(point u1,point u2,pointv1,point v2){

returnopposite_side(u1,u2,v1,v2)&&opposite_side(v1,v2,u1,u2);

}

//线段交点请另外判线段相交(同时还是要判断是否平行!)

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))

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