foo.cc: In function 'int main()':
foo.cc:71:18: warning: 'len' may be used uninitialized [-Wmaybe-uninitialized]
   71 |         len = div(num, k, len);
      |               ~~~^~~~~~~~~~~~~
foo.cc:54:9: note: 'len' was declared here
   54 |     int len;
      |         ^~~
foo.cc:38:13: warning: 'len' may be used uninitialized [-Wmaybe-uninitialized]
   38 |         int len;
      |             ^~~

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