foo.cc: In function 'int main()':
foo.cc:6:11: warning: right operand of comma operator has no effect [-Wunused-value]
    6 |  cin>>a,b,c,d;
      |           ^
foo.cc:6:13: warning: right operand of comma operator has no effect [-Wunused-value]
    6 |  cin>>a,b,c,d;
      |             ^
foo.cc:6:14: warning: right operand of comma operator has no effect [-Wunused-value]
    6 |  cin>>a,b,c,d;
      |              ^
foo.cc:7:9: warning: 'b' is used uninitialized in this function [-Wuninitialized]
    7 |  cout<<a+b+c+d;
      |        ~^~
foo.cc:7:11: warning: 'c' is used uninitialized in this function [-Wuninitialized]
    7 |  cout<<a+b+c+d;
      |        ~~~^~
foo.cc:7:14: warning: 'd' is used uninitialized in this function [-Wuninitialized]
    7 |  cout<<a+b+c+d;
      |              ^

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