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Return Values

The Main method can be of the type void:

static void Main() 

It can also return an int:

static int Main() 
   return 0;


In this example, the program contains two classes, Factorial and MainClass. The Main method, which resides in the MainClass class, is used to read a number from the keyboard, invoke the Fac method from the Factorial class, and calculate and display the factorial of the input number.

// cs_main.cs
using System; 
public class Factorial 
   public static long Fac(long i) 
      return ((i <= 1) ? 1 : (i * Fac(i-1))); 

class MainClass 
   public static void Main() 
      // Read a string from the keyboard:
      Console.Write("Enter an integer: ");

      string s = Console.ReadLine();

      // Convert the string to long:
         long num = Int64.Parse(s);
         Console.WriteLine("The Factorial of {0} is {1}.",
                           num, Factorial.Fac(num)); 
      catch (System.FormatException)
         Console.WriteLine("Invalid input specified");



Sample Output

Enter an integer: 5
The Factorial of 5 is 120.

See Also

Command-Line Arguments | Main

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