CGAL geometry kernel primitives

[petrasvestartas]

Hi,

I have very naive and simple question, but it pops out from time to time.

How do you normally copy simple geometry kernels such point, line, segement, direction, plane?

Is it enough to write:
Point a = b;
Or I always must use constructor:
Point a(b);

[afabri]

a = b; is fine.

[petrasvestartas]

Thank you

[lrineau]

You question is a C++ question, and it is not specific to CGAL. All you have to know is that geometry kernel primitives are class templates, and they have copy constructors.

Copy initialization

Point a = b;

This is a copy initialization. As Point is a class, and both a and b are of type Point, and b is not a prvalue, then the copy constructor of Point is called to initialize a with a copy of b.

Direct initialization

Point a(b);

This is a direct initilization. Point is a class and both a and b are of type Point, and b is not a prvalue, then the copy constructor of Point is called to initialize a with a copy of b.

Conclusion

Point a = b;
Point aa(b);

For CGAL geometric objects, those two ways of initialization are completely equivalent.

Side-note

Point a;
a = b

That is completely different: that is a value initialization (that class the default constructor) followed by a assignment (that calls the copy assignment operator of the class).