Tutorial 44 Recursion: A Useful Trick Up Your Sleeve

//Tutorial 44 Recursion: A Useful Trick Up Your Sleeve
//simple
public class App {

    public static void main(String[] args) {

        //E.g. 4! = 4*3*2*1
        System.out.println(factorial(5));
    }
    private static int factorial(int value) {
        System.out.println(value); //5, 4, 3, 2, 1

        if(value == 1) { //this to stop the continuos recursion to infinitey/StackOverflow, stop at the value of 1
            return 1;
        }
        return factorial(value - 1) * value; //the factorial (#)! (ie: 5 *3*2*1 = 120)

    }
}


//---------------------------------------------------------------------------------------------------------------------------------------
/* Run Results:
5
4
3
2
1
120
*/






//---------------------------------------------------------------------------------------------------------------------------------------
//Practice
public class App {

    public static void main(String[] args) {
        System.out.println(calculate(7));
    }
    private static int calculate(int value) {
        System.out.println(value);

        if(value == 1) {
            return 1;
        }
    return calculate(value - 1) * value;
    }
}

/* Run Results:
7
6
5
4
3
2
1
5040
*/