Coding Schools

OOPS in C#
C# Data Types
Boxing and Unboxing in C#
Garbage Collection in C#
C# - Conditional Statements
C# - Loops
Interfaces in C#
Generics in C#
Collections in C#
C# 8.0 new features
C# Singleton Design Pattern
C# Factory Design Pattern
LINQ in C#
C# - Program to Find Prime Numbers
C# - Fibonacci Sequence
C# - Factorial of a number
C# - Recursive methods
C# - Anonymous Methods
C# - String Methods
C# TDD - XUnit
C# TDD - NUnit
C# Multiton Design Pattern
C# Facade Design Pattern
C# Abstract Factory Design Pattern
C# Decorator Design Pattern
C# Composite Design Pattern

C# - Factorial of a number

Here's a C# program that calculates and prints the factorial of a given number:

csharp

using System;

class Program
{
    static void Main()
    {
        Console.Write("Enter a number: ");
        if (int.TryParse(Console.ReadLine(), out int number))
        {
            long factorial = Factorial(number);
            Console.WriteLine($"The factorial of {number} is {factorial}.");
        }
        else
        {
            Console.WriteLine("Invalid input. Please enter a valid number.");
        }
    }

    // Method to calculate factorial using recursion
    static long Factorial(int n)
    {
        if (n <= 1)
        {
            return 1;
        }
        return n * Factorial(n - 1);
    }
}

Explanation:

Main Method:
- Prompts the user to enter a number.
- Uses int.TryParse to safely parse the user input into an integer.
- Calls the Factorial method to calculate the factorial of the entered number.
- Prints the result.
Factorial Method:
- Uses recursion to calculate the factorial.
- If n is less than or equal to 1, it returns 1 (base case).
- Otherwise, it returns n multiplied by the factorial of n-1.

Iterative Approach:

For larger numbers or to avoid the overhead of recursion, you can also implement an iterative approach:

csharp

using System;

class Program
{
    static void Main()
    {
        Console.Write("Enter a number: ");
        if (int.TryParse(Console.ReadLine(), out int number))
        {
            long factorial = FactorialIterative(number);
            Console.WriteLine($"The factorial of {number} is {factorial}.");
        }
        else
        {
            Console.WriteLine("Invalid input. Please enter a valid number.");
        }
    }

    // Method to calculate factorial using iteration
    static long FactorialIterative(int n)
    {
        long result = 1;
        for (int i = 2; i <= n; i++)
        {
            result *= i;
        }
        return result;
    }
}

Explanation of the Iterative Approach:

FactorialIterative Method:
- Initializes result to 1.
- Uses a for loop to multiply result by each integer from 2 up to n.
- Returns the computed factorial.

Choose the approach that best fits your needs and the constraints of your program. Let me know if you have any specific requirements or further questions!