初学c++ 错误信息解释与解决

1，non-const static data
member must be initialized out of line

 解释：非const的静态值初始化必须在类外。

正确的写法：

#include<iostream>

int static i = 0;

class Base{

}

/*******************************************************************************************************************************************************************************



2 in-class initializer for static data member of type 'const double' is a GNU extension

解释链接：http://stackoverflow.com/questions/370283/why-cant-i-have-a-non-integral-static-const-member-in-a-class

类中的静态常量声明只可以是整形。

正确的写法:

#include<iostream>

class Base{

const  int  static  i = 0;

constexpr  double  static  d = 1.0;

};