/in/foo.c: In function 'main':
/in/foo.c:9:9: warning: 'sum' may be used uninitialized [-Wmaybe-uninitialized]
    9 |         printf("%d\n",sum);
      |         ^~~~~~~~~~~~~~~~~~
/in/foo.c:5:13: note: 'sum' was declared here
    5 |     int n,i,sum;
      |             ^~~