C# Command Line Arguments

Command Line Arguments are the arguments that are provided along with the run command in command line or terminal. These arguments can be used to set the initial state of the application.

For example, consider that you built an application, and you have two modes: test, production. In test mode, you print all the debug lines. So, when you start an application, you can provide a command line argument that can make the application run in test or production mode.

Note: Main() function receives the command line arguments as string array string[]. You can use this array to access the command line arguments.

Example – Command Line Arguments in C#

In the following example, we have Main() function with string[] as arguments in its definition. We shall print the number of arguments received and the arguments as well.

Program.cs

using System;

namespace CSharpExamples {
    class Program {
        static void Main(string[] args) {
            Console.WriteLine("Number of Arguments : " + args.Length);  
            Console.WriteLine("Arguments provided in the command line are: ");  
            foreach (string str in args) {  
                Console.WriteLine(str);       
            }  
        }
    }
}

Output

PS D:\workspace\csharp\HelloWorld> dotnet run TutorialKart C#
Number of Arguments : 2
Arguments provided in the command line are:
TutorialKart
C#

After the command dotnet run, we have provided two strings TutorialKart and C# as arguments. Hence the number of arguments printed is 2.

Example – Program that does not consider command line arguments

You can define your Main() function with no string[] as argument. In this case, even if you provide command line arguments, those are not captured as arguments to the Main() function.

Program.cs

using System;

namespace CSharpExamples {
    class Program {
        static void Main() {
            Console.WriteLine("The program does not consider any arguments");  
        }
    }
}

Output

PS D:\workspace\csharp\HelloWorld> dotnet run
The program does not consider any arguments
PS D:\workspace\csharp\HelloWorld> dotnet run TutorialKart
The program does not consider any arguments

Conclusion

In this C# Tutorial, we learned about Command Line Arguments in C#, how to provide these arguments to the program, how to access these values with examples.