Swift Program – Factorial of a Number

In this tutorial, we will go through Swift programs to find the factorial of a given number, in different approaches like using for-in loop, recursion, while loop, etc.

Swift Factorial Program using For-in Loop

In the following program, we will use for-in loop for computing factorial of a given number.

main.swift

func factorial(n: Int) -> Int {
    var result = 1
    if(n > 0) {
        for i in 1...n {
            result *= i
        }
    }
    return result
}

let num = 4
let result = factorial(n: num)
print("\(num)! = \(result)")

Output

Swift Factorial Program using Recursion

In the following program, we will use recursion mechanism for computing factorial of a given number.

main.swift

func factorial(n: Int) -> Int {
    return n <= 1 ? 1 : n * factorial(n: n - 1)
}

let num = 5
let result = factorial(n: num)
print("\(num)! = \(result)")

Output

Swift Factorial Program using While Loop

In the following program, we will use while loop for computing factorial of a given number.

main.swift

func factorial(n: Int) -> Int {
    var result = 1
    var i = 1
    while i <= n {
        result *= i
        i += 1
    }
    return result
}

let num = 5
let result = factorial(n: num)
print("\(num)! = \(result)")

Output

Conclusion

In this Swift Tutorial, we learned how to find the factorial of a given number using for-in statement, recursion, etc., with examples.