/in/foo.cc: In function 'long long int gcd(long long int, long long int)':
/in/foo.cc:8:21: warning: left operand of comma operator has no effect [-Wunused-value]
         return (b,a%b);
                     ^
/in/foo.cc: In function 'int main()':
/in/foo.cc:22:12: warning: 'd' may be used uninitialized in this function [-Wmaybe-uninitialized]
     cout<<a/d*b<<endl;
           ~^~