/in/foo.cc: In function 'int main()':
/in/foo.cc:9:30: warning: 'a' may be used uninitialized [-Wmaybe-uninitialized]
    9 |                 for(int j=1;j<=a;j++)
      |                             ~^~~
/in/foo.cc:5:15: note: 'a' was declared here
    5 |         int n,a;
      |               ^