Structures in C#

A structure is a data type in C# that combines different data variables into a single unit. The keyword struct is used to create the structures.

Some of the salient points about structures are as follows:

1. Structures are created using the struct keyword.
2. Interfaces can be implemented using interfaces.
3. Structures have default, no parameter constructors that cannot be replaced. They initialize all the fields to default values
4. There is no destructor definition for structures.
5. There is no concept of inheritance in structures.
6. There is no specification for structure members such as virtual, protected, abstract etc.

Structure Definition

A new structure requires a structure definition. It starts with the struct keyword and contains the structure name. Then the structure body is provided within curly braces. It may contain multiple data variables of different types.

The syntax of a structure definition is given as follows:

struct NameOfStructure
{
    // Member variables
}

In the above syntax, the keyword struct is used which is followed by the NameOfStructure. Then the structure body is provided.

A program that demonstrates structures is given as follows:

Source Code: Program that demonstrates structures in C#

using System;
namespace StructureDemo
{    
  struct Student
{
  public int rno;
  public string name;
  public double marks;
};  
 public class Test
 {
  public static void Main(string[] args)
  {
     Student s1;   
     Student s2;
     Student s3;
     s1.rno = 1;
     s1.name = "Mary";
     s1.marks = 75.5;
     s2.rno = 2;
     s2.name = "Jack";
     s2.marks = 98.0;
     s3.rno = 3;
     s3.name = "Susan";
     s3.marks = 35.0;
     Console.WriteLine("Student Details");
     Console.WriteLine("Roll Number = {0}", s1.rno);
     Console.WriteLine("Name = {0}", s1.name);
     Console.WriteLine("Marks = {0}", s1.marks);
     Console.WriteLine("Roll Number = {0}", s2.rno);
     Console.WriteLine("Name = {0}", s2.name);
     Console.WriteLine("Marks = {0}", s2.marks);
     Console.WriteLine("Roll Number = {0}", s3.rno);
     Console.WriteLine("Name = {0}", s3.name);
     Console.WriteLine("Marks = {0}", s3.marks);     
  }
}
}

The output of the above program is as follows:

Student Details

Roll Number = 1
Name = Mary
Marks = 75.5

Roll Number = 2
Name = Jack
Marks = 98

Roll Number = 3
Name = Susan
Marks = 35

Now let us understand the above program.

The structure student is defined using the keyword struct. It contains 3 data variables representing the Roll number, Name and Marks of the student. The code snippet for this is as follows:

struct Student
{
  public int rno;
  public string name;
  public double marks;
};

The function main() contains 3 structure objects i.e. s1, s2 and s3. Then the values data are assigned to the structure objects. Finally, the student details are printed. The code snippet for this is as follows:

 public static void Main(string[] args)
  {
     Student s1;   
     Student s2;
     Student s3;
     s1.rno = 1;
     s1.name = "Mary";
     s1.marks = 75.5;
     s2.rno = 2;
     s2.name = "Jack";
     s2.marks = 98.0;
     s3.rno = 3;
     s3.name = "Susan";
     s3.marks = 35.0;
     Console.WriteLine("Student Details");
     Console.WriteLine("Roll Number = {0}", s1.rno);
     Console.WriteLine("Name = {0}", s1.name);
     Console.WriteLine("Marks = {0}", s1.marks);
     Console.WriteLine("Roll Number = {0}", s2.rno);
     Console.WriteLine("Name = {0}", s2.name);
     Console.WriteLine("Marks = {0}", s2.marks);
     Console.WriteLine("Roll Number = {0}", s3.rno);
     Console.WriteLine("Name = {0}", s3.name);
     Console.WriteLine("Marks = {0}", s3.marks);
  }

Structures vs Classes

Structures are similar to classes but lighter versions of them. Some of the differences of structures and classes are given as follows: