foo.cc: In function 'int main()':
foo.cc:6:23: warning: unused variable 'r' [-Wunused-variable]
    6 |         int y,m,d,sum,r;
      |                       ^
foo.cc:28:20: warning: 'sum' may be used uninitialized in this function [-Wmaybe-uninitialized]
   28 |                 sum+=1;
      |                 ~~~^~~

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