/in/foo.cc: In function 'int WeekdayOfTheFirstDay(int, int)':
/in/foo.cc:11:25: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   if(i%400==0 || i%4==0 && i%100!=0)
                  ~~~~~~~^~~~~~~~~~~
/in/foo.cc:31:32: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
    if(year%400==0 || year%4==0 && year%100!=0)
                      ~~~~~~~~~~^~~~~~~~~~~~~~
/in/foo.cc: In function 'void daying(int, int)':
/in/foo.cc:54:28: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   if(year%400==0||year%4==0&&year%100!=0)
                   ~~~~~~~~~^~~~~~~~~~~~~