/in/foo.cc: In member function 'void Datetime::Pass(int)':
/in/foo.cc:36:30: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
  if(year%400==0 || year%4==0 && year%100!=0)
                    ~~~~~~~~~~^~~~~~~~~~~~~~
/in/foo.cc: In member function 'int Datetime::cal(Datetime)':
/in/foo.cc:126:3: warning: this 'else' clause does not guard... [-Wmisleading-indentation]
   else
   ^~~~
/in/foo.cc:128:4: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'else'
    for(m=m1+2; m<=13; m++)
    ^~~
/in/foo.cc: In member function 'int Datetime::MD(int, int)':
/in/foo.cc:76:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^
/in/foo.cc: In member function 'int Datetime::Month(int, int)':
/in/foo.cc:156:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^