foo.cc: In function 'int main()':
foo.cc:8:17: warning: right operand of comma operator has no effect [-Wunused-value]
    8 |         cin>>a,b;
      |                 ^
foo.cc:9:17: warning: 'b' is used uninitialized [-Wuninitialized]
    9 |         cout<<a+b;
      |                 ^

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