/in/foo.c: In function 'main':
/in/foo.c:37:9: error: 'r' undeclared (first use in this function)
   37 |         r[i] = (float)sum / 5;
      |         ^
/in/foo.c:37:9: note: each undeclared identifier is reported only once for each function it appears in
/in/foo.c:50:26: error: 'avg_arr' undeclared (first use in this function)
   50 |         printf("%.1f\n", avg_arr[i]);
      |                          ^~~~~~~
/in/foo.c:31:11: warning: unused variable 'a' [-Wunused-variable]
   31 |     float a[n];
      |           ^