/in/foo.cc: In function 'int main()':
/in/foo.cc:24:17: warning: comparison of constant '500' with boolean expression is always true [-Wbool-compare]
   24 |     else if (0<a<500)
      |              ~~~^~~~
/in/foo.cc:24:15: warning: comparisons like 'X<=Y<=Z' do not have their mathematical meaning [-Wparentheses]
   24 |     else if (0<a<500)
      |              ~^~