template<class T>
struct point { T x, y; };
typedef list< point<?> > line;
struct rect
{
union { int x1, left; };
union { int x2, right; };
union { int y1, top; };
union { int y2, bottom; };
};
templates, structs, typedefs & lists
Author
all in one!
how might i get this to compile?
first we create struct point, which will take ints, floats, doubles, or what have you, as long as they are the same, right..?
then we want "line" to be a list of points, so long as each point has the same type.
putting "int" in for the ? will compile, however, that's not what I want. replacing it with "T" also doesnt work. leaving the <?> out altogether doesnt work either.. so ya.. not really sure.
also, just for clarification,
will let me create a rect, and i can refer to left-most vertical line of the rectangle as "x1" or "left" and they are interchangable, correct? ie, if i change 'x1', it changes 'left'?
You can't use "T" in your typedef, because it is outside of the template declaration, which ended at the end of your struct. If you don't want to use an actual type in your typedef, I'm not sure what you're trying to do..
Edit: I suppose you could do something like this:
And yes, that struct of unions will work as you expect it to.
Edit: I suppose you could do something like this:
template <class T>struct point { typedef std::list<point<T> > line; T x, y;};typedef point<int> IntPoint;IntPoint::line MyListOfIntPoints;And yes, that struct of unions will work as you expect it to.
Let me guess, you want to define the line type, and then be able to use the line type later on, with varous types for the points' members? Like:
line<int> IntLine;line<float> FloatLine;template<class T>struct point { T x, y; };template<class T>typedef list< point<T> > line;
Try this instead
Hope this helps!
[edit]
Doh! Agony, beat me to it! He is also correct on it not being supported by C++.
[/edit]
template<class T>struct point { T x, y; };template<class T>typedef list< point<T> > line;Hope this helps!
[edit]
Doh! Agony, beat me to it! He is also correct on it not being supported by C++.
[/edit]
Author
Quote:template<class T>
struct point { T x, y; };
template<class T>
typedef list< point<T> > line;
tried that before either of you suggested it, but thanks.
don't see why that shouldn't work... *shakes a fist at the C++ makers*
Is my method unacceptable? It will work.... Just wondering if I'm way off in what I think you're aiming for..
Yeah, it's definitely a highly desired feature. I battled with this problem for a week when I was developing a console parser only to find out it wasn't my code, but the code in general.
Also, from what I've read on google, pragma Fury's example is the most common work around for this.
Happy coding!
Also, from what I've read on google, pragma Fury's example is the most common work around for this.
Happy coding!
Author
what is the dif between pragma fury's suggestion, and
typedef list< point<int> > line;
?
typedef list< point<int> > line;
?
Quote:Original post by darkzerox
what is the dif between pragma fury's suggestion, and
typedef list< point<int> > line;
?
None, really.. except that you define both the point type and the list to contain that point type with a single typedef. It also scopes the list to the type of point that it will contain, so it's nicely packaged.
This topic is closed to new replies.
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