foo.cc: In function 'int main()':
foo.cc:32:17: warning: 'v' may be used uninitialized in this function [-Wmaybe-uninitialized]
  cout << p <<" "<< v;
  ~~~~~~~~~~~~~~~^~~~
foo.cc:32:14: warning: 'p' may be used uninitialized in this function [-Wmaybe-uninitialized]
  cout << p <<" "<< v;
              ^~~

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