foo.cc: In function 'int main()':
foo.cc:24:22: warning: 'b' may be used uninitialized in this function [-Wmaybe-uninitialized]
  cout<<n<<'='<<a<<'+'<<b;
  ~~~~~~~~~~~~~~~~~~~~^~~
foo.cc:24:19: warning: 'a' may be used uninitialized in this function [-Wmaybe-uninitialized]
  cout<<n<<'='<<a<<'+'<<b;
                   ^~~

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