/in/foo.cc: In function 'bool leap(int)':
/in/foo.cc:4:15: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
  return y%4==0&&y%100!=0 || y%400==0;
         ~~~~~~^~~~~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:9:2: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
  for (int i=year;i<=y1;i++)
  ^~~
/in/foo.cc:11:3: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'for'
   cout <<ans;
   ^~~~