What is the best way to indicate that a double value has not been initialized?

Question

I have a class CS which is to represent the co-ordinate system in 3D i.e.(x, y, z)

class CS
{
  private:
        double x;
        double y;
        double z         


        

Answer 1

One way to get the semantics of what you want would be to have the datatype of the coordinates be a type that carries with it a value indicating whether it has been assigned. Something like this.

template
class CoordinateValue {
   public:
       CoordinateValue() : uninitialized(true), val(0) {}
       CoordinateValue(T x) : uninitialized(false), val(x) {}
       void setVal(T x) {val = x; uninitialized= false}
       // Trivial getters
    private:
       T val;
       bool uninitialized;
};

I'd prefer something like this over cuter methods unless memory is really scarce for some reason.

If the coordinates are either all default or all set, then you can have a single flag rather than a coordinate datatype that includes the flag.