/in/foo.cc: In function 'int main()':
/in/foo.cc:2:25: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
 #define num(x) ((x%4==0 && x%100!=0 || x%400==0)?366:365)
                         ^
/in/foo.cc:7:23: note: in expansion of macro 'num'
     for (int i=1901,o=num(i); --n; i++,o=num(i))
                       ^~~