Struct & Enum in C#

C# Structs

In C#, classes and structs are blueprints that are used to create instance of a class. Structs are used for lightweight objects such as Color, Rectangle, Point etc.

Unlike class, structs in C# are value type than reference type. It is useful if you have data that is not intended to be modified after creation of struct.

 Let’s see a simple example of struct Rectangle which has two data members width and height.

using System;  
public struct Rectangle  {  
    public int width, height;  

}  
public class TestStructs  {  
    public static void Main()  {  
        Rectangle r = new Rectangle();  
        r.width = 4;  
        r.height = 5;  
        Console.WriteLine("Area of Rectangle is: " + (r.width * r.height));  
    }  
}  

Output:

Area of Rectangle is: 20

C# Enum

Enum in C# is also known as enumeration. It is used to store a set of named constants such as season, days, month, size etc. The enum constants are also known as enumerators. Enum in C# can be declared within or outside class and structs.

Enum constants has default values which starts from 0 and incremented to one by one. But we can change the default value.

Points to remember:

• enum has fixed set of constants
• enum improves type safety
• enum can be traversed

Let’s see a simple example of C# enum.

using System;  
public class EnumExample  {  
    public enum Season { WINTER, SPRING, SUMMER, FALL }    

    public static void Main()  {  
        int x = (int)Season.WINTER;  
        int y = (int)Season.SUMMER;  
        Console.WriteLine("WINTER = {0}", x);  
        Console.WriteLine("SUMMER = {0}", y);  
    }  
}  

Output:

WINTER = 0
SUMMER = 2

We can also change the starting index, see the below code.

public enum Season { WINTER=10, SPRING, SUMMER, FALL }    

In order to traverse all values we can use getNames() or getValues() methods.

using System;  
public class EnumExample  {  
    public enum Days { Sun, Mon, Tue, Wed, Thu, Fri, Sat };  

    public static void Main()  {  
        foreach (string s in Enum.GetNames(typeof(Days)))  {  
            Console.WriteLine(s);  
        }  
    }  
}  

Output:

Sun
Mon
Tue
Wed
Thu
Fri
Sat

Try the following example in the editor below.

Create a structure named ‘student’, containing three members: name (string), rollno(int) and marks(int).