foo.cc: In function ‘int main()’:
foo.cc:8:26: warning: ‘n’ may be used uninitialized [-Wmaybe-uninitialized]
    8 |                 for(j=1;j<=n;j++)
      |                         ~^~~
foo.cc:5:13: note: ‘n’ was declared here
    5 |         int n,i,j;
      |             ^