#include<iostream>
using namespace std;
class point
{
public:
    point(double a, double b,double c,double d);
    friend void dist(point*p);
    void show();
private:
    double u;
    double w;
    double x;
    double y;
    double z;
};
point::point(double a, double b, double c, double d )
{
    u = a;
    w = b;
    x = c;
    y = d;
}
void dist(point*p)
{
    p->z=sqrt((p->u -p->x)*(p->u -p-> x)+(p->w -p->y)*(p->w -p->y));
    
}
void point::show()
{
    cout << "the distance of the two point is:" << z << endl;
}
int main()
{
    point chih(8,6,4,2);
    point *p;
    p = &chih;
    chih. show();
}