The enum keyword is used to declare an enumeration, a distinct type consisting of a set of named constants called the enumerator list. It is user defined data types. Every enumeration type has an underlying type, which can be any integral type except char. The default underlying type of the enumeration elements is int. By default, the first enumerator has the value 0, and the value of each successive enumerator is increased by 1

How use enum keyword in our program

Example 1:

enum Days { Sat = 1, Sun, Mon, Tue, Wed, Thu, Fri }; 
protected void Page_Load(object sender, EventArgs e) 
{  
   int x = (int)Days.Sun; 
   Response.Write(x); 
}