在头文件中定义并在cpp中实现的C++结构

Question

当我在另一个类中使用它时,我如何确保我实现的某些颜色保持其价值？

struct.h

struct Color{
   unsigned char r;
   unsigned char g;
   unsigned char b;
};
Color someColor;
//if i define the color here it says...:
Color someColor = {255,255,255}; //error: data member inializer not allowed

struct.cpp

struct::Color someColor = {255,255,255};

someotherclass.cpp

struct *str = new struct();
str->someColor.r //is not the correct value /not set

Answer 1

您需要在标头中声明它:

extern Color someColor;

并在.cpp文件中定义它:

Color someColor = {255, 255, 255};

请注意,您的语法struct::Color极具误导性.它被解析为struct ::Color,并且在C++术语中,它等同于::Color或仅仅Color(除非你在命名空间内).