/in/foo.cc: In function 'int main()':
/in/foo.cc:13:15: warning: 's' may be used uninitialized [-Wmaybe-uninitialized]
   13 |         printf("%0.2f",s/n);
      |         ~~~~~~^~~~~~~~~~~~~
/in/foo.cc:6:18: note: 's' was declared here
    6 |         double a,s;
      |                  ^