/in/foo.cc: In function 'bool LeapYear(int)':
/in/foo.cc:7:32: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
  if(year%4!=0  ||  year%100==0 && year%400!=0)
                    ~~~~~~~~~~~~^~~~~~~~~~~~~~
/in/foo.cc: In function 'int DaySum(int, int)':
/in/foo.cc:55:9: warning: 'sum' may be used uninitialized in this function [-Wmaybe-uninitialized]
  return sum;
         ^~~