Valid variant of Main() in C#

The Main method is the entry point for all C# programs. It defines what the class does when executed. When you run a C# application, the runtime looks for the Main method and begins execution from there.

Syntax

There are several valid variants of the Main method in C# −

static void Main()
static void Main(string[] args)
static int Main()
static int Main(string[] args)

Parameters

• static − the object is not needed to access static members. The Main method must be static so the runtime can call it without creating an instance of the class.

• void/int − return type of the method. Use void when no return value is needed, or int to return an exit code.

• Main − entry point for any C# program. Program execution begins here.

• string[] args − optional parameter for command line arguments passed to the program.

Using Main with void Return Type

Example

using System;

namespace Program {
   public class Demo {
      public static void Main(string[] args) {
         Console.WriteLine("Welcome!");
         Console.WriteLine("Program completed successfully.");
      }
   }
}

The output of the above code is −

Welcome!
Program completed successfully.

Using Main with int Return Type

Example

using System;

namespace Program {
   public class Demo {
      public static int Main(string[] args) {
         Console.WriteLine("Application started");
         
         try {
            Console.WriteLine("Processing completed");
            return 0; // Success
         }
         catch (Exception ex) {
            Console.WriteLine("Error: " + ex.Message);
            return 1; // Error
         }
      }
   }
}

The output of the above code is −

Application started
Processing completed

Using Command Line Arguments

Example

using System;

namespace Program {
   public class Demo {
      public static void Main(string[] args) {
         Console.WriteLine("Number of arguments: " + args.Length);
         
         if (args.Length > 0) {
            Console.WriteLine("Arguments passed:");
            for (int i = 0; i 

The output of the above code is −

Number of arguments: 0
No arguments provided.


Valid Main Method Variants Comparison

Conclusion

The Main method serves as the entry point for C# applications and must be static. You can choose from four valid variants depending on whether you need command line arguments and return values. The most commonly used variant is static void Main(string[] args).