/in/foo.cc: In function 'int main()':
/in/foo.cc:12:2: error: '__int64' was not declared in this scope
  __int64 m;
  ^~~~~~~
/in/foo.cc:12:2: note: suggested alternative: '__int64_t'
  __int64 m;
  ^~~~~~~
  __int64_t
/in/foo.cc:13:6: error: 'log10' was not declared in this scope
  p=n*log10(n+0.);
      ^~~~~
/in/foo.cc:14:2: error: 'm' was not declared in this scope
  m=(__int64)p;
  ^
/in/foo.cc:11:11: warning: unused variable 'a' [-Wunused-variable]
  double p,a;
           ^