/in/foo.cc:68:42: warning: multi-character character constant [-Wmultichar]
   char FILE_NAME2[] = FILE_NAME, inc[] = '.in', outc[] = '.out';
                                          ^~~~~
/in/foo.cc:68:58: warning: multi-character character constant [-Wmultichar]
   char FILE_NAME2[] = FILE_NAME, inc[] = '.in', outc[] = '.out';
                                                          ^~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:68:42: error: initializer fails to determine size of 'inc'
   char FILE_NAME2[] = FILE_NAME, inc[] = '.in', outc[] = '.out';
                                          ^~~~~
/in/foo.cc:68:42: error: array must be initialized with a brace-enclosed initializer
/in/foo.cc:68:58: error: initializer fails to determine size of 'outc'
   char FILE_NAME2[] = FILE_NAME, inc[] = '.in', outc[] = '.out';
                                                          ^~~~~~
/in/foo.cc:68:58: error: array must be initialized with a brace-enclosed initializer
/in/foo.cc:69:50: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings]
   strcat(FILE_NAME2, inc); strcat(FILE_NAME, outc);
                                                  ^