cwh_34_recursion.java

public class cwh_34_recursion {
    // factorial(0) = 1
    // factorial(n) = n * n-1 *....1
    // factorial(5) = 5 * 4 * 3 * 2 * 1 = 120
    // factorial(n) = n * factorial(n-1)

    static int factorial(int n){
        if(n==0 || n==1){
            return 1;
        }
        else{
            return n * factorial(n-1);
        }
    }
    static int factorial_iterative(int n){
        if(n==0 || n==1){
            return 1;
        }
        else{
            int product = 1;
            for (int i=1;i<=n;i++){ // 1 to n
                product *= i;
            }
            return product;
        }
    }
    public static void main(String[] args) {
        int x = 0;
        System.out.println("The value of factorial x is: " + factorial(x));
        System.out.println("The value of factorial x is: " + factorial_iterative(x));
    }
}