急急急！c++题目的 题目关于定义类line描述直线！高分！

class line{
public:
line(double a,double b,double c,double d);
bool isJiao(line line2);
double x1;
double y1;
double x2;
double y2;
};
line::line(double a,double b,double c,double d){
x1=a;
y1=b;
x2=c;
y2=d;
}
bool line::isJiao(line line2){
if((x1==x2) && (line2.x1==line2.x2)){
return false;
}
else if(((x1==x2) && (line2.x1!=line2.x2)) || ((x1!=x2) && (line2.x1==line2.x2)))
{
return true;
}
else {
double k1;
double k2;
k1=(y2-y1) / (x2-x1);
k2=(line2.y2-line2.y1) / (line2.x2-line2.x1);
double cha=k1-k2;
if(cha<0.0000001){
return false;
}
else
return true;
}
}

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