foo.cc: In function 'int main()':
foo.cc:6:2: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
  if(a%5==0&&b%5==0); cout<<2<<' '<<a+b<<endl;
  ^~
foo.cc:6:22: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
  if(a%5==0&&b%5==0); cout<<2<<' '<<a+b<<endl;
                      ^~~~

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