what does the double& for

[jayadelgado]

in this code where i have to make the source for intersection what does the double& mean?

void intersection(double m1, double b1, double m2, double b2, 
                  double& i_x, double& i_y)

[vlad from moscow]

& means reference to an object. So the function accpets not a copy of an argument but a reference to it. As the result any changes of parameter in the function body will keep in the original argument.