/in/foo.cc: In function 'int main()':
/in/foo.cc:12:28: warning: 'sum' may be used uninitialized [-Wmaybe-uninitialized]
   12 |                         sum+=30-d1+d2;
      |                         ~~~^~~~~~~~~~
/in/foo.cc:5:25: note: 'sum' was declared here
    5 |         int d1,d2,m1,m2,sum;
      |                         ^~~