c++ 类的静态、常量初始化

https://blog.csdn.net/Motarookie/article/details/129687111

常见错误总结

• non-const static data member must be initialized out of line
  https://blog.csdn.net/nlforever/article/details/9313587
  非const的静态值初始化必须在类外。
  如：

  class CA{
  public:
  static int var2 = 0;
  };

  声明var2时如果赋值会报错