在switch语句中使用const int变量

Question

我正在使用带有-std = c ++ 11标志的gcc.在我的课程定义中,我有以下内容:

private:
   const int   January     = 1,
               February    = 2,
               March       = 3,
               ...

在我的实现中,我有一个switch语句.

switch (currentMonth)
{
   case January:
      returnString = "January";
      break;
   case February:
      returnString = "February";
      break;
   case March:
      returnString = "March";
      break;
   ...

这似乎应该有效,因为月份是不变的; 但是,gcc给了我

calendar.cpp:116:12: error: ‘this’ is not a constant expression

在switch语句的每个案例上.为什么这是错的？

Answer 1

非静态类成员不是常量表达式.试试这个:

static constexpr int January = 1;