C Language Macro Application-------#define STR (X) #X

#: Arguments are converted to strings

#define STR (x)    #x#define MAX    100

STR (max) is expanded to "Max"

This has a flaw, if the entry is a macro, and can not print out the value of the macro (such as the previous example, only print out Max, and does not print the value of max)

You can expand a macro under

#define _str (x)    #x#define STR (x)    _str (x)#define MAX    100

STR (MAX) is replaced in the following order

STR (100)

_STR (100)

"100"

Final output 100

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Can be applied to the output of enumerations and macros