foo.cc: In function 'int main()':
foo.cc:22:14: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
  if(year%4==0&&month>=3||year%400==0&&month>=3)
     ~~~~~~~~~^~~~~~~~~~
foo.cc:24:12: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
  if(month<3&&year%4!=0||year%400!=0)
     ~~~~~~~^~~~~~~~~~~
foo.cc: In function 'int ly(int)':
foo.cc:31:6: warning: unused variable 'day' [-Wunused-variable]
  int day;
      ^~~
foo.cc:32:6: warning: unused variable 'month' [-Wunused-variable]
  int month;
      ^~~~~
foo.cc:33:6: warning: 'year' is used uninitialized in this function [-Wuninitialized]
  int r4=year%4;
      ^~
foo.cc: In function 'int main()':
foo.cc:10:18: warning: 'leap' is used uninitialized in this function [-Wuninitialized]
  int leap=ly(leap); 
                  ^
foo.cc: In function 'int fj(int)':
foo.cc:55:7: warning: 'leap' may be used uninitialized in this function [-Wmaybe-uninitialized]
    day=27+leap;
    ~~~^~~~~~~~
foo.cc: In function 'int main()':
foo.cc:11:12: warning: 'month' is used uninitialized in this function [-Wuninitialized]
  int day=fj(month); 
          ~~^~~~~~~