/in/foo.cc: In function 'int main()':
/in/foo.cc:9:11: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
  if(y%4==0&&y%100!=0||y%400==0)a 
     ~~~~~~^~~~~~~~~~
/in/foo.cc:9:32: error: 'a' was not declared in this scope
  if(y%4==0&&y%100!=0||y%400==0)a 
                                ^