What are the main parts of a C# program?

The main parts of a C# program include −

• Namespace declaration
• A class
• Class methods
• Class attributes
• A Main method
• Statements and Expressions
• Comments

Understanding these components is essential for writing effective C# programs. Each part serves a specific purpose in organizing and executing your code.

Basic C# Program Structure

The following example demonstrates a simple C# program with all the essential parts −

using System;

namespace Demo {
   class Program {
      // Class attribute (field)
      static string message = "Our first program in C#!";

      // Main method - entry point
      static void Main(string[] args) {
         // Method call statement
         DisplayMessage();
      }

      // Class method
      static void DisplayMessage() {
         Console.WriteLine(message);
      }
   }
}

The output of the above code is −

Our first program in C#!

Breakdown of Program Components

Using Statement

The using System; directive includes the System namespace, which contains fundamental classes like Console. Multiple using statements can be added for different namespaces.

Namespace Declaration

A namespace is a collection of related classes. The Demo namespace contains the Program class. Namespaces help organize code and prevent naming conflicts.

Class Declaration

The class Program defines a container for data (attributes) and methods. Classes are the fundamental building blocks of object-oriented programming in C#.

Main Method

The Main method is the entry point where program execution begins. It must be static and can accept command-line arguments through the string[] args parameter.

Program with Comments

using System;

namespace StudentApp {
   // Student class with attributes and methods
   class Student {
      // Class attributes
      public string name;
      public int age;

      // Constructor method
      public Student(string studentName, int studentAge) {
         name = studentName;  // Assign parameter to field
         age = studentAge;
      }

      // Display method
      public void ShowDetails() {
         /* Multi-line comment:
            This method displays student information */
         Console.WriteLine($"Name: {name}, Age: {age}");
      }

      // Main method - program entry point
      static void Main(string[] args) {
         Student student1 = new Student("Alice", 20);
         student1.ShowDetails();
      }
   }
}

The output of the above code is −

Name: Alice, Age: 20

Key Components Summary

Conclusion

Every C# program consists of essential components: namespaces for organization, classes as containers, the Main method as the entry point, and statements for program logic. Understanding this structure is fundamental to writing well-organized C# applications.