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  1. #define MACRO(abc, def) {#def ## #abc}
  2.  
  3. char result[10] = MACRO(abc, def);
  4.  
Compilation error #stdin compilation error #stdout 0s 0KB
stdin
Standard input is empty
compilation info
prog.cpp:3:33: error: pasting ""def"" and ""abc"" does not give a valid preprocessing token
 char result[10] = MACRO(abc, def);
                                 ^
prog.cpp:1:27: note: in definition of macro ‘MACRO’
 #define MACRO(abc, def) {#def ## #abc}
                           ^
stdout
Standard output is empty