foo.cc: In function 'int LeftCout(char*, int)':
foo.cc:46:2: error: 'strrev' was not declared in this scope
  strrev(shu);
  ^~~~~~
foo.cc:46:2: note: suggested alternative: 'strsep'
  strrev(shu);
  ^~~~~~
  strsep
foo.cc:52:1: warning: no return statement in function returning non-void [-Wreturn-type]
 }
 ^
foo.cc: In function 'int main()':
foo.cc:22:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%[^\n]",s);
  ~~~~~^~~~~~~~~~~~

自豪的采用HydroJudge(https://github.com/hydro-dev/Hydro)进行评测。