foo.cc: In function 'int main()':
foo.cc:6:5: error: 'distance' was not declared in this scope; did you mean 'std::distance'?
    6 |     distance = sqrt( (x1-x2)*(x1-x2)+(y1-y2)*(y1-y2) );
      |     ^~~~~~~~
      |     std::distance
In file included from /nix/store/42izybv2fz3ps5pcg3dvcmn85pc9406y-gcc-11.3.0/include/c++/11.3.0/bits/stl_algobase.h:66,
                 from /nix/store/42izybv2fz3ps5pcg3dvcmn85pc9406y-gcc-11.3.0/include/c++/11.3.0/bits/char_traits.h:39,
                 from /nix/store/42izybv2fz3ps5pcg3dvcmn85pc9406y-gcc-11.3.0/include/c++/11.3.0/ios:40,
                 from /nix/store/42izybv2fz3ps5pcg3dvcmn85pc9406y-gcc-11.3.0/include/c++/11.3.0/istream:38,
                 from /nix/store/42izybv2fz3ps5pcg3dvcmn85pc9406y-gcc-11.3.0/include/c++/11.3.0/sstream:38,
                 from /nix/store/42izybv2fz3ps5pcg3dvcmn85pc9406y-gcc-11.3.0/include/c++/11.3.0/complex:45,
                 from /nix/store/42izybv2fz3ps5pcg3dvcmn85pc9406y-gcc-11.3.0/include/c++/11.3.0/ccomplex:39,
                 from stdc++.h:54:
/nix/store/42izybv2fz3ps5pcg3dvcmn85pc9406y-gcc-11.3.0/include/c++/11.3.0/bits/stl_iterator_base_funcs.h:138:5: note: 'std::distance' declared here
  138 |     distance(_InputIterator __first, _InputIterator __last)
      |     ^~~~~~~~

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