How do I give the correct parameters without "&" or "*" to the called method?

Question

I am new here quite new to writing code in c++ and currently run into following problem:

I use the library wykobi which deals with geometry and solved many of my prior problems, but now I want to create a triangle using it and cant figure out how to call the required method correctly.

std::string x_str(argv[2]);
std::string y_str(argv[3]);
double x = atof(x_str.c_str());
double y = atof(y_str.c_str());

[...]

double x2;
x2 = double(orientation.direction.x)+angleRightx;
double y2;
y2 = double(orientation.direction.y)+angleRighty;
double x3;
x3 = double(orientation.direction.x)+angleLeftx;
double y3;
y3 = double(orientation.direction.y)+angleLefty;

wykobi::triangle<wykobi::Float,2> clip_boundry = wykobi::make_triangle<wykobi::Float,2>(&x,&y, &x2,&y2, &x3,&y3);
wykobi::polygon<wykobi::Float,2> clipped_polygon;
wykobi::algorithm::sutherland_hodgman_polygon_clipper<wykobi::point2d<wykobi::Float> >(clip_boundry,wykPG,clipped_polygon);

I tried something similar before creating a circle, which worked perfectly fine:

wykobi::circle<wykobi::Float> circle;
circle.x = x;
circle.y = y;
circle.radius = dist;
wykobi::polygon<wykobi::Float,2> clip_boundry = wykobi::make_polygon<wykobi::Float>(circle,100);
wykobi::polygon<wykobi::Float,2> clipped_polygon;
wykobi::algorithm::sutherland_hodgman_polygon_clipper<wykobi::point2d<wykobi::Float> >(clip_boundry,wykPG,clipped_polygon);

Now the problem on compiling is:

error: no matching function for call to 'make_triangle(double*, double*, double*, double*, double*, double*)'

When I remove the ampersands:

wykobi::triangle<wykobi::Float,2> clip_boundry = wykobi::make_triangle<wykobi::Float,2>(x,y, x2,y2, x3,y3);

The error on comiling is:

error: no matching function for call to 'make_triangle(double&, double&, double&, double&, double&, double&)'

And finally the method I call looks like this:

template<typename T> inline triangle<T,2> make_triangle(const T& x1, const T& y1, const T& x2, const T& y2, const T& x3, const T& y3);

So I wonder what do I have to change to give the correct parameters?

Thanks in advance!

Answer 1

You have at least the following issues:

1) Mixing up double with wykobi::Float.

2) You are passing two template parameters, whereas the function only expects one.

3) Template deduction could hopefully be done here.

Try this code:

wykobi::make_triangle(x, y, x2, y2, x3, y3);

or

wykobi::make_triangle<wykobi::Float>(x, y, x2, y2, x3, y3);

or

wykobi::make_triangle<double>(x, y, x2, y2, x3, y3);

but make sure these parameters are wykobi::Float or double, respectively. Do not mix them up unless wykobi::Float is some kind of typedef.

Also, do not try passing addresses because this template function does not expect a pointer.

Answer 2

The function make_triangle<wykobi::Float..() requires that you pass references to wykobi::Float, but instead, you are trying to pass variables of type double.

I don't know the library, but see if there is some explicit or implicit conversion from double to the wykobi::Float type

e.g.

wykobi::Float wx1 = x;

or

wykobi::Float wx1 = new wykobi::Float(x);

and then pass these to the make_triangle function.

Also, as per Lazlo's comment, the constant 2 does not appear valid for a template parameter - this should be a type, e.g. int.