Static const double in c++

Question

Is this the proper way to use a static const variable? In my top level class (Shape)

#ifndef SHAPE_H
#define SHAPE_H

class Shape
{
public:

    static cons         


        

Answer 1

Static floating-point data members must be defined and initialized in a source file. The one-definition rule forbids a definition outside the class {} block in the header, and only integral data members are allowed to be initialized inside the class {} block.

This is also unfortunate because, being an algebraic value, having the immediate value on hand could be nice for optimization, rather than loading from a global variable. (The difference is likely to be inconsequential, though.)

There is a solution, though!

class Shape
{
public:
    static double pi()
        { return 3.14159265; }

private:
    double originX;
    double originY;
};

Inline function definitions, including static ones, are allowed inside the class{} block.

Also, I recommend using M_PI from , which you should also get from .