/in/foo.cc: In function 'CComplex& operator+(CComplex&, CComplex&)':
/in/foo.cc:22:12: warning: reference to local variable 'a1' returned [-Wreturn-local-addr]
   CComplex a1(a.a+b.a, a.b+b.b);
            ^~
/in/foo.cc: In function 'CComplex& operator*(CComplex&, CComplex&)':
/in/foo.cc:27:12: warning: reference to local variable 'a2' returned [-Wreturn-local-addr]
   CComplex a2(a.a*b.a - a.b*b.b, a.a*b.b + a.b*b.a);
            ^~