jarak 2 titik in c++

#include <cstdlib>
#include <iostream>
#include <math.h>
#include <conio.h>

using namespace std;
class jarak {
public :
void baca1();
void baca2();
void tulis1();

private :
double a1,a2,a3,a4;
};
void jarak::baca1 (){
cout<<”Masukkan X1 :”;cin>>a1;
cout<<”Masukkan Y1 :”;cin>>a2;
cout<<”Masukkan X2 :”;cin>>a3;
cout<<”Masukkan Y2 :”;cin>>a4;
cout<<endl;
}