/in/foo.c: In function 'main':
/in/foo.c:11:11: warning: format '%d' expects argument of type 'int', but argument 2 has type 'long int' [-Wformat=]
  printf("%d\n",s2-s1);
           ^
/in/foo.c: In function 'sum':
/in/foo.c:20:12: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   if(i%4==0&&i%100!=0||i%400==0) s+=366;
      ~~~~~~^~~~~~~~~~
/in/foo.c:22:11: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
  if(y%4==0&&y%100!=0||y%400==0)x[2]=29;
     ~~~~~~^~~~~~~~~~