foo.cc: In member function ‘complex& complex::operator+(complex&)’:
foo.cc:32:24: warning: reference to local variable ‘h’ returned [-Wreturn-local-addr]
   32 |                 return h;
      |                        ^
foo.cc:31:25: note: declared here
   31 |                 complex h(x1, x2);
      |                         ^
foo.cc: In member function ‘complex& complex::operator*(complex&)’:
foo.cc:39:24: warning: reference to local variable ‘h’ returned [-Wreturn-local-addr]
   39 |                 return h;
      |                        ^
foo.cc:38:25: note: declared here
   38 |                 complex h(x1, x2);
      |                         ^