foo.cc: In function 'int main()':
foo.cc:31:16: warning: 'sum' may be used uninitialized in this function [-Wmaybe-uninitialized]
  cout<<d<<" "<<sum<<endl;
                ^~~
foo.cc:31:11: warning: 'd' may be used uninitialized in this function [-Wmaybe-uninitialized]
  cout<<d<<" "<<sum<<endl;
           ^~~

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