/in/foo.c: In function 'main':
/in/foo.c:15:12: warning: 'sum' may be used uninitialized [-Wmaybe-uninitialized]
   15 |         if (sum == i)
      |            ^
/in/foo.c:4:19: note: 'sum' was declared here
    4 |         int n,i,j,sum;
      |                   ^~~