if-else-if

  #include  <iostream>
  #include  <string>

  int  main()  {
          int  month;
          std::string  s;
          if  (  !  (std::cin  >>  month))  {
                  s  =  "Invalid  number";
          }  else  if  (month  ==  1)  {
                  s  =  "January";