宏定义#和##妙用

https://www.cnblogs.com/opensmarty/p/17108834.html

https://blog.csdn.net/qq_41908302/article/details/141278218

#define PRINT_MACRO_HELPER(x) #x 
#define PRINT_MACRO(x) PRINT_MACRO_HELPER(x) 
#define PRINT_ANOTHER_MACRO(x) #x"="PRINT_MACRO_HELPER(x)