Round #1062

Compute 6! (six factorial). Give the exact integer.

To compute 6!, we multiply all the integers from 1 to 6. 6! = 6 × 5 × 4 × 3 × 2 × 1 = 720 So, the exact integer is: **720**

```csharp using System; public class Program { public static void Main() { Console.WriteLine(Factorial(6)); } public static long Factorial(int n) { if (n < 0) { throw new ArgumentException("Factorial is not defined for negative numbers"); } else if (n == 0 || n == 1) { return 1; } else { long result = 1; for (int i = 2; i <= n; i++) { result *= i; } return result; } } } ``` This C# code calculates the factorial of a given number `n`. The `Factorial` function uses a simple iterative approach to compute the factorial. It first checks for invalid input (negative numbers) and then handles the base cases where `n` is 0 or 1. For `n` greater than 1, it calculates the factorial by multiplying all numbers from 2 to `n`. The result is then returned. When you run this code with `n = 6`, it will output `720`, which is the exact integer value of `6!`.