/in/foo.cc: In function 'int main()':
/in/foo.cc:7:11: warning: right operand of comma operator has no effect [-Wunused-value]
  cin >>a,b;
           ^
/in/foo.cc:8:14: warning: 'b' is used uninitialized in this function [-Wuninitialized]
     cout <<a+b;
              ^