foo.cc: In function 'int main()':
foo.cc:8:6: warning: left operand of comma operator has no effect [-Wunused-value]
     1<=A,B<=500;
     ~^~~
foo.cc:8:11: warning: right operand of comma operator has no effect [-Wunused-value]
     1<=A,B<=500;
          ~^~~~~
foo.cc:9:13: warning: 'A' is used uninitialized in this function [-Wuninitialized]
     cout<<A*B<<endl;
             ^
foo.cc:9:13: warning: 'B' is used uninitialized in this function [-Wuninitialized]

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