定义一个枚举类型，用来描述一年12个月，一月、二月、···、十二月，并编写一个程序，根据用户输入的年份，输出该年各月的英文名及天数。-The definition of an enumerated type that describes 12 months a year, in January, February ,, December, and write a program based on user input of the year, the output of each month o