急！ 用c++程序求两条直线的交点

比较粗略的答案
#include <iostream.h>
class line
{ double a,b,c;
public:
line ( double a1, double b1, double c1)
{a=a1;b=b1;c=c1;}
friend void setpoint(line &A,line &B);
};
void setpoint(line &A,line &B)
{ double x;
if(A.a/B.a!=A.b/B.b)
{x=-100;
do
{
if(( (-A.c-A.a*x)/A.b - (-B.c-B.a*x)/B.b ) < 0.00001)
break;

x=x+0.00001;
}while(1);
cout<<x<<" "<<(-A.c-A.a*x)/A.b;}
else cout<<"error"<<endl;}

void main ()
{line A(-2,-1,4),B(1,-10,-3);
setpoint(A,B);
}