How to calculate the factorial of a number in Go?

To calculate the factorial of a number in Go, you can use a recursive function or a loop. Here's an example of both approaches:

Recursive Approach:

func factorialRecursive(n int) int {
    if n == 0 {
        return 1
    }
    return n * factorialRecursive(n-1)
}

func main() {
    n := 5
    result := factorialRecursive(n)
    fmt.Printf("The factorial of %d is %d\n", n, result)
}

Loop Approach:

func factorialLoop(n int) int {
    result := 1
    for i := 1; i <= n; i++ {
        result *= i
    }
    return result
}

func main() {
    n := 5
    result := factorialLoop(n)
    fmt.Printf("The factorial of %d is %d\n", n, result)
}

Both approaches will yield the same result. The recursive approach uses a base case to terminate the recursion when n reaches 0, and the loop approach calculates the factorial by multiplying the numbers from 1 to n.