code: public ComplexFloat addi(ComplexFloat c, ComplexFloat result) {
      if (this == result) {
        r += c.r;
        i += c.i;
      } else {
        result.r = r + c.r;
        result.i = i + c.i;
      }
      return result;
    }
docs: Add two complex numbers in-place
  
  @param c      other complex number
  @param result complex number where result is stored
  @return same as result