/in/foo.cc: In function 'int main()':
/in/foo.cc:6:11: warning: right operand of comma operator has no effect [-Wunused-value]
  cin>>a,b,c,d;
           ^
/in/foo.cc:6:13: warning: right operand of comma operator has no effect [-Wunused-value]
  cin>>a,b,c,d;
             ^
/in/foo.cc:6:14: warning: right operand of comma operator has no effect [-Wunused-value]
  cin>>a,b,c,d;
              ^