/in/foo.cc:3:1: error: ISO C++ forbids declaration of 'leap' with no type [-fpermissive]
    3 | leap(int y)
      | ^~~~
/in/foo.cc: In function 'int leap(int)':
/in/foo.cc:6:36: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
    6 |         leap= y%400==0 || y%100!=0 && y%4==0;
      |                           ~~~~~~~~~^~~~~~~~~
/in/foo.cc: At global scope:
/in/foo.cc:12:1: error: ISO C++ forbids declaration of 'monthday' with no type [-fpermissive]
   12 | monthday(int y,int m)
      | ^~~~~~~~
/in/foo.cc:22:1: error: ISO C++ forbids declaration of 'yearday' with no type [-fpermissive]
   22 | yearday(int y,int m)
      | ^~~~~~~