foo.cc: In function ‘int main()’:
foo.cc:9:28: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses]
    9 |                 if((y%4==0)&&(y%100!=0) or (y%400==0))
      |                    ~~~~~~~~^~~~~~~~~~~~
foo.cc:7:9: warning: ‘m’ is used uninitialized [-Wuninitialized]
    7 |         if(m==2)
      |         ^~
foo.cc:6:15: note: ‘m’ was declared here
    6 |         int y,m;
      |               ^
foo.cc:6:13: warning: ‘y’ may be used uninitialized [-Wmaybe-uninitialized]
    6 |         int y,m;
      |             ^