/in/foo.cc:8:15: error: 'm' has not been declared
  Date(int y=0,m=0,d=0):year(y),month(m),day(d)
               ^
/in/foo.cc:8:19: error: 'd' has not been declared
  Date(int y=0,m=0,d=0):year(y),month(m),day(d)
                   ^
/in/foo.cc: In constructor 'Date::Date(int, int, int)':
/in/foo.cc:8:38: error: 'm' was not declared in this scope
  Date(int y=0,m=0,d=0):year(y),month(m),day(d)
                                      ^
/in/foo.cc:8:45: error: 'd' was not declared in this scope
  Date(int y=0,m=0,d=0):year(y),month(m),day(d)
                                             ^
/in/foo.cc: In member function 'int Date::isLeapYear(int)':
/in/foo.cc:12:28: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   if(year%400==0||year%4==0&&year%100!=0)
                   ~~~~~~~~~^~~~~~~~~~~~~