foo.cc:122:25: warning: multi-character character constant [-Wmultichar]
     constexpr uint e0 = '\0\0\0\1', e1 = '\0\0\1\0', e2 = '\0\1\0\0', e3 = '\1\0\0\0';
                         ^~~~~~~~~~
foo.cc:122:42: warning: multi-character character constant [-Wmultichar]
     constexpr uint e0 = '\0\0\0\1', e1 = '\0\0\1\0', e2 = '\0\1\0\0', e3 = '\1\0\0\0';
                                          ^~~~~~~~~~
foo.cc:122:59: warning: multi-character character constant [-Wmultichar]
     constexpr uint e0 = '\0\0\0\1', e1 = '\0\0\1\0', e2 = '\0\1\0\0', e3 = '\1\0\0\0';
                                                           ^~~~~~~~~~
foo.cc:122:76: warning: multi-character character constant [-Wmultichar]
     constexpr uint e0 = '\0\0\0\1', e1 = '\0\0\1\0', e2 = '\0\1\0\0', e3 = '\1\0\0\0';
                                                                            ^~~~~~~~~~
foo.cc:124:27: warning: multi-character character constant [-Wmultichar]
     for (uint i = 0, c0 = '0000'; i != 10; ++i, c0 += e0)
                           ^~~~~~
foo.cc: In function 'const Complex* init(int)':
foo.cc:51:63: warning: suggest parentheses around '+' inside '<<' [-Wparentheses]
     for (int i = 18; i != -1; --i) ROOT[1 << i] = ROOT[1 << i + 1] * ROOT[1 << i + 1];
                                                             ~~^~~
foo.cc:51:82: warning: suggest parentheses around '+' inside '<<' [-Wparentheses]
     for (int i = 18; i != -1; --i) ROOT[1 << i] = ROOT[1 << i + 1] * ROOT[1 << i + 1];
                                                                                ~~^~~
foo.cc: In member function 'IO_Tp& IO_Tp::operator<<(uint)':
foo.cc:164:40: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]
       *--reinterpret_cast<uint *&>(_pos) = m[x % 10000], x /= 10000;
                                        ^
foo.cc:166:40: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]
       *--reinterpret_cast<uint *&>(_pos) = m[x % 10000], x /= 10000;
                                        ^
foo.cc:167:38: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]
     *--reinterpret_cast<uint *&>(_pos) = m[x];
                                      ^
foo.cc: In constructor 'IO_Tp::IO_Tp()':
foo.cc:130:10: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
     fread(_I_Buffer, 1, _I_Buffer_Size, stdin);
     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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