enum的用法

参考资料：

C++ enum枚举用法攻略（超详细）
它就是一个值，直接使用就可以了。

正文：

#include <iostream>
using namespace std;
// Declare the enumerated type
enum Roster { Tom = 1, Sharon, Bill, Teresa, John };
// Sharon - John will be assigned default values 2-5.
int main() {
  int who;
  cin >> who;
  switch (who) {
    case Tom:
      cout << "Tom's birthday is January 3.\n";
      break;
    case Sharon:
      cout << "Sharon's birthday is April 22.\n";
      break;
    case Bill:
      cout << "Bill's birthday is December 19.\n";
      break;
    case Teresa:
      cout << "Teresa's birthday is February 2.\n";
      break;
    case John:
      cout << "John's birthday is June 17.\n";
      break;
    default:
      cout << "Invalid selection\n";
  }
  return 0;
}