foo.cc: In function ‘int main()’:
foo.cc:27:45: error: expected ‘)’ before ‘，2’
   27 |     ans= sqrt (pow((dist[n-1].x - dist[0].x)，2.0)+pow((dist[n-1].y - dist[0].y), 2.0))；
      |                   ~                         ^~~
      |                                             )
foo.cc:27:19: error: no matching function for call to ‘pow(double)’
   27 |     ans= sqrt (pow((dist[n-1].x - dist[0].x)，2.0)+pow((dist[n-1].y - dist[0].y), 2.0))；
      |                ~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from foo.cc:3:
/nix/gcc/include/c++/14-20241116/cmath:1074:5: note: candidate: ‘template<class _Tp, class _Up> constexpr typename __gnu_cxx::__promote_2<_Tp, _Up>::__type std::pow(_Tp, _Up)’
 1074 |     pow(_Tp __x, _Up __y)
      |     ^~~
/nix/gcc/include/c++/14-20241116/cmath:1074:5: note:   candidate expects 2 arguments, 1 provided
In file included from /nix/glibc-2.40-66-dev/include/features.h:511,
                 from /nix/gcc-14-20241116/include/c++/14-20241116/x86_64-unknown-linux-gnu/bits/os_defines.h:39,
                 from /nix/gcc-14-20241116/include/c++/14-20241116/x86_64-unknown-linux-gnu/bits/c++config.h:680,
                 from cstdio:41:
/nix/glibc-2.40-66-dev/include/bits/mathcalls.h:155:1: note: candidate: ‘double pow(double, double)’
  155 | __MATHCALL_VEC (pow,, (_Mdouble_ __x, _Mdouble_ __y));
      | ^~~~~~~~~~~~~~
/nix/glibc-2.40-66-dev/include/bits/mathcalls.h:155:1: note:   candidate expects 2 arguments, 1 provided
/nix/gcc/include/c++/14-20241116/cmath:380:3: note: candidate: ‘constexpr long double std::pow(long double, long double)’
  380 |   pow(long double __x, long double __y)
      |   ^~~
/nix/gcc/include/c++/14-20241116/cmath:380:3: note:   candidate expects 2 arguments, 1 provided
/nix/gcc/include/c++/14-20241116/cmath:376:3: note: candidate: ‘constexpr float std::pow(float, float)’
  376 |   pow(float __x, float __y)
      |   ^~~
/nix/gcc/include/c++/14-20241116/cmath:376:3: note:   candidate expects 2 arguments, 1 provided
foo.cc:28:18: error: ‘i’ was not declared in this scope
   28 |     for (int i=0;i<n;i++)
      |                  ^